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Any replacements are listed further down

[248] **viXra:1612.0398 [pdf]**
*submitted on 2016-12-29 12:32:03*

**Authors:** Irina I. Bodrenko

**Comments:** 3 Pages.

The some properties of hypersurfaces F3 in Euclidean space E4 of nonzero
Laplacian of the second fundamental form b are studied in this report.

**Category:** Geometry

[247] **viXra:1611.0035 [pdf]**
*submitted on 2016-11-02 18:56:08*

**Authors:** Dragan Turanyanin

**Comments:** 3 Pages.

This spiral (given in polar coordinates r, theta) can be seen as a missing member of the set of known spirals.

**Category:** Geometry

[246] **viXra:1611.0003 [pdf]**
*submitted on 2016-11-01 01:37:29*

**Authors:** Brian Ekanyu

**Comments:** 3 Pages.

This paper proves a geometric theorem about the Hebrew nation that is the Patriarchs Abraham, Isaac and Jacob and the Twelve tribes of Israel. The circle represents the state of Israel.

**Category:** Geometry

[245] **viXra:1610.0367 [pdf]**
*submitted on 2016-10-30 14:48:27*

**Authors:** Dragan Turanyanin

**Comments:** 6 Pages.

The aim of this review is firstly, to present again a new family of polar curves (e.g. thurals [1]) and secondly, to introduce their so called inpolars as main objects of one original geometrical transformation [2]. Addendum is completely new with a brief analysis of s-thural.

**Category:** Geometry

[244] **viXra:1610.0076 [pdf]**
*submitted on 2016-10-06 19:47:24*

**Authors:** James A. Smith

**Comments:** 5 Pages.

To the collections of problems solved via Geometric Algebra (GA) in References 1-13, this document adds a solution, using only dot products, to the Problem of Apollonius. The solution is provided for completeness and for contrast with the GA solutions presented in Reference 3.

**Category:** Geometry

[243] **viXra:1610.0054 [pdf]**
*submitted on 2016-10-04 18:46:06*

**Authors:** James A. Smith

**Comments:** 15 Pages.

Drawing mainly upon exercises from Hestenes's New Foundations for Classical Mechanics, this document presents, explains, and discusses common solution strategies. Included are a list of formulas and a guide to nomenclature.

**Category:** Geometry

[242] **viXra:1609.0365 [pdf]**
*submitted on 2016-09-25 18:17:04*

**Authors:** James A. Smith

**Comments:** 5 Pages.

This document adds to the collection of GA solutions to plane-geometry problems, most of them dealing with tangency, that are presented in References 1-7. Reference 1 presented several ways of solving the CPP limiting case of the Problem of Apollonius. Here, we use ideas from Reference 6 to solve that case in yet another way.

**Category:** Geometry

[241] **viXra:1609.0082 [pdf]**
*submitted on 2016-09-06 19:08:36*

**Authors:** Marvin Ray Burns

**Comments:** 8 Pages. This classic paper shows the utter simplicity of the geometric description of the MRB constant (oeis.org/A037077).

The MRB constant is the upper limit point of the sequence of partial sums defined by S(x)=sum((-
1)^n*n^(1/n),n=1..x). The goal of this paper is to show that the MRB constant is geometrically
quantifiable. To “measure” the MRB constant, we will consider a set, sequence and alternating series of
the nth roots of n. Then we will compare the length of the edges of a special set of hypercubes or ncubes
which have a content of n. (The two words hypercubes and n-cubes will be used synonymously.)
Finally, we will look at the value of the MRB constant as a representation of that comparison, of the length of the edges of a special set of hypercubes, in units of dimension 1/ (units of dimension 2 times
units of dimension 3 times units of dimension 4 times etc.). For an arbitrary example we will use units of
length/ (time*mass* density*…).

**Category:** Geometry

[240] **viXra:1608.0328 [pdf]**
*submitted on 2016-08-24 18:28:40*

**Authors:** James A. Smith

**Comments:** 38 Pages.

This document adds to the collection of solved problems presented in References [1]-[6]. The solutions presented herein are not as efficient as those in [6], but they give additional insight into ways in which GA can be used to solve this problem. After reviewing, briefly, how reflections and rotations can be expressed and manipulated via GA, it solves the CLP limiting case of the Problem of Apollonius in three ways, some of which identify the the solution circles' points of tangency with the given circle, and others of which identify the solution circles' points of tangency with the given line. For comparison, the solutions that were developed in [1] are presented in an Appendix.

**Category:** Geometry

[239] **viXra:1608.0217 [pdf]**
*submitted on 2016-08-19 21:41:57*

**Authors:** James A. Smith

**Comments:** 10 Pages.

The new solutions presented herein for the CLP and CCP limiting cases of the Problem of Apollonius are much shorter and more easily understood than those provided by the same author in References 1 and 2. These improvements result from (1) a better selection of angle relationships as a starting point for the solution process; and (2) better use of GA identities to avoid forming troublesome combinations of terms within the resulting equations.

**Category:** Geometry

[238] **viXra:1608.0153 [pdf]**
*submitted on 2016-08-15 04:33:03*

**Authors:** Xu Chen

**Comments:** 8 Pages.

In this article, we will discuss a new operator $d_{C}$ on $W(\mathfrak{g})\otimes\Omega^{*}(M)$ and to construct a new Cartan model for equivariant cohomology. We use the new Cartan model to construct the corresponding BRST model and Weil model, and discuss the relations between them.

**Category:** Geometry

[237] **viXra:1608.0103 [pdf]**
*submitted on 2016-08-09 15:55:41*

**Authors:** Robert B. Easter

**Comments:** 4 Pages.

This note on quadrics and pseudoquadrics inversions in hyperpseudospheres shows that the inversions produce different results in a three-dimensional spacetime. Using Geometric Algebra, all quadric and pseudoquadric entities and operations are in the G(4,8) Double Conformal Space-Time Algebra (DCSTA). Quadrics at zero velocity are purely spatial entities in x y z-space that are hypercylinders in w x y z-spacetime. Pseudoquadrics represent quadrics in a three-dimensional (3D) x y w, y z w, or z x w spacetime with the pseudospatial w-axis that is associated with time w=c t. The inversion of a quadric in a hyperpseudosphere can produce a Darboux pseudocyclide in a 3D spacetime that is a quartic hyperbolic (infinite) surface, which does not include the point at infinity. The inversion of a pseudoquadric in a hyperpseudosphere can produce a Darboux pseudocyclide in a 3D spacetime that is a quartic finite surface. A quadric and pseudoquadric can represent the same quadric surface in space, and their two different inversions in a hyperpseudosphere represent the two types of reflections of the quadric surface in a hyperboloid.

**Category:** Geometry

[236] **viXra:1607.0369 [pdf]**
*submitted on 2016-07-19 15:02:18*

**Authors:** Jeffrey Joseph Wolynski

**Comments:** 2 Pages. 3 illustrations

It is shown that simple geometry could have been used to make the discovery that planet formation is stellar evolution.

**Category:** Geometry

[235] **viXra:1607.0356 [pdf]**
*submitted on 2016-07-18 07:10:10*

**Authors:** Ion Patrascu, Florentin Smarandache

**Comments:** 11 Pages.

In this article, we define the Lucas’s inner
circles and we highlight some of their properties.

**Category:** Geometry

[234] **viXra:1607.0355 [pdf]**
*submitted on 2016-07-18 07:11:14*

**Authors:** Florentin Smarandache

**Comments:** 3 Pages.

We present here the magic square of order n.

**Category:** Geometry

[233] **viXra:1607.0349 [pdf]**
*submitted on 2016-07-18 07:18:12*

**Authors:** Florentin Smarandache

**Comments:** 5 Pages.

Postulatul V al lui Euclid se enunta sub forma: daca o dreapta, care intersecteaza doua drepte, formeaza unghiuri interioare de aceeasi parte
mai mici decat doua unghiuri drepte, aceste drepte, prelungite la infinit, se intalnesc in parte a unde unghiurile interioare sunt mai mici decal doua unghiuri drepte.

**Category:** Geometry

[232] **viXra:1607.0348 [pdf]**
*submitted on 2016-07-18 07:18:58*

**Authors:** Ion Patrascu, Florentin Smarandache

**Comments:** 9 Pages.

In this article, we highlight some metric
properties in connection with Neuberg's circles and triangle. We recall some results that are necessary.

**Category:** Geometry

[231] **viXra:1607.0346 [pdf]**
*submitted on 2016-07-18 07:21:25*

**Authors:** Florentin Smarandache

**Comments:** 3 Pages.

It is a lot easier to deny the Euclid`s five postulates, than Hilbert`s twenty thorough axiom.

**Category:** Geometry

[230] **viXra:1607.0341 [pdf]**
*submitted on 2016-07-18 07:27:33*

**Authors:** Florentin Smarandache

**Comments:** 2 Pages.

In 1969, fascinat de geometrie, am construit un spatiu partial eueliadian si partial neeuclidian
in acelasi timp, inlocuind postulatul V al lui Euclid (axioma paralelelor) prin urmatoarea
propozitie stranie continand cinci asertiuni.

**Category:** Geometry

[229] **viXra:1607.0331 [pdf]**
*submitted on 2016-07-18 07:38:11*

**Authors:** Florentin Smarandache

**Comments:** 2 Pages.

Les axes radicals de n cercles d'un même plan, pris deux à deux, dont les centres ne sont pas alignes, sont concourants.

**Category:** Geometry

[228] **viXra:1607.0330 [pdf]**
*submitted on 2016-07-18 07:40:58*

**Authors:** Florentin Smarandache

**Comments:** 2 Pages.

In 1969, intrigued by geometry I constructed a partially euclidean and partially non-Euclidean space.

**Category:** Geometry

[227] **viXra:1607.0325 [pdf]**
*submitted on 2016-07-18 07:53:17*

**Authors:** Ion Patrascu, Florentin Smarandache

**Comments:** 11 Pages.

In this article, we emphasize the radical axis of the Lemoine’s circles.

**Category:** Geometry

[226] **viXra:1607.0323 [pdf]**
*submitted on 2016-07-18 07:55:17*

**Authors:** Ion Patrascu, Florentin Smarandache

**Comments:** 9 Pages.

In this article, we define the first Droz-Farny’s circle, we establish a connection between it and a concyclicity theorem, then we generalize this theorem, leading to the generalization of Droz-Farny’s circle.

**Category:** Geometry

[225] **viXra:1607.0322 [pdf]**
*submitted on 2016-07-18 07:56:54*

**Authors:** Ion Patrascu, Florentin Smarandache

**Comments:** 9 Pages.

In this article, we prove the theorem
relative to the second Droz-Farny’s circle, and a sentence that generalizes it.

**Category:** Geometry

[224] **viXra:1607.0304 [pdf]**
*submitted on 2016-07-18 08:23:01*

**Authors:** Ion Patrascu, Florentin Smarandache

**Comments:** 25 Pages.

In this article, we solve problems of geometric constructions only with the ruler, using known theorems.

**Category:** Geometry

[223] **viXra:1607.0303 [pdf]**
*submitted on 2016-07-18 08:23:58*

**Authors:** Ion Patrascu, Florentin Smarandache

**Comments:** 6 Pages.

The late mathematician Cezar Cosnita, using the barycenter coordinates, proves two theorems which are the subject of this article.

**Category:** Geometry

[222] **viXra:1607.0302 [pdf]**
*submitted on 2016-07-18 08:24:44*

**Authors:** Ion Patrascu, Florentin Smarandache

**Comments:** 9 Pages.

In this article, we prove several theorems about the radical center and the radical circle of ex-inscribed circles of a triangle and calculate the radius of the circle from vectorial considerations.

**Category:** Geometry

[221] **viXra:1607.0260 [pdf]**
*submitted on 2016-07-18 05:32:50*

**Authors:** Florentin Smarandache

**Comments:** 14 Pages.

It is possible to de-formatize entirely Hilbert`s group of axioms of the Euclidean Geometry, and to construct a model such that none of this fixed axiom holds.

**Category:** Geometry

[220] **viXra:1607.0258 [pdf]**
*submitted on 2016-07-18 05:34:44*

**Authors:** Ion Patrascu, Florentin Smarandache

**Comments:** 9 Pages.

This article highlights some properties of
Apollonius’s circle of second rank in connection with the adjoint circles and the second Brocard’s triangle.

**Category:** Geometry

[219] **viXra:1607.0253 [pdf]**
*submitted on 2016-07-18 05:40:32*

**Authors:** Ion Patrascu, Florentin Smarandache

**Comments:** 9 Pages.

In this article, we prove the theorem relative to the circle of the 6 points and, requiring on this circle to have three other remarkable triangle’s points, we obtain the circle of 9 points (the Euler’s Circle).

**Category:** Geometry

[218] **viXra:1607.0240 [pdf]**
*submitted on 2016-07-18 06:07:02*

**Authors:** Florentin Smarandache

**Comments:** 5 Pages.

Let P, L be two sets, and r a relation included in PxL.

**Category:** Geometry

[217] **viXra:1607.0229 [pdf]**
*submitted on 2016-07-18 06:36:40*

**Authors:** Florentin Smarandache

**Comments:** 4 Pages.

Dans ces paragraphss on présente "trois généralisations du célèbre théorème de Ceva.

**Category:** Geometry

[216] **viXra:1607.0227 [pdf]**
*submitted on 2016-07-18 06:39:23*

**Authors:** Florentin Smarandache

**Comments:** 2 Pages.

Let’s consider the points A1,...,An situated on the same plane, and B1,...,Bn situated on another plane, such that the lines A1B1 are concurrent. Let’s prove that if the lines AiAj and BiBj are concurrent, then their intersecting points are collinear.

**Category:** Geometry

[215] **viXra:1607.0225 [pdf]**
*submitted on 2016-07-18 06:41:46*

**Authors:** Florentin Smarandache

**Comments:** 2 Pages.

What happens in 3-space when the poiygon is replaced by a polyhedron?

**Category:** Geometry

[214] **viXra:1607.0209 [pdf]**
*submitted on 2016-07-18 07:05:18*

**Authors:** Ion Patrascu, Florentin Smarandache

**Comments:** 7 Pages.

In this article, we get to Lemoine's circles
in a different manner than the known one.

**Category:** Geometry

[213] **viXra:1607.0208 [pdf]**
*submitted on 2016-07-18 07:06:38*

**Authors:** Ion Patrascu, Florentin Smarandache

**Comments:** 8 Pages.

For the calculus of the first Lemoine’s circle, we will first prove.

**Category:** Geometry

[212] **viXra:1607.0166 [pdf]**
*submitted on 2016-07-13 22:10:37*

**Authors:** James A. Smith

**Comments:** 11 Pages.

This document adds to the collection of solved problems presented in [1]-[4]. After reviewing, briefly, how reflections and rotations can be expressed and manipulated via GA, it solves the LLP limiting case of the Problem of Apollonius in two ways.

**Category:** Geometry

[211] **viXra:1607.0086 [pdf]**
*submitted on 2016-07-07 07:28:29*

**Authors:** Kermit Ohlrabi

**Comments:** 14 pages

Let ${j_{\mathscr{{Y}}}}$ be a M\"obius homomorphism. Every student is aware that there exists a freely Gaussian meager, globally tangential polytope. We show that every continuous triangle is finitely Desargues. The work in \cite{cite:0} did not consider the almost Torricelli, co-locally $\varphi$-standard case. Now this leaves open the question of convergence.

**Category:** Geometry

[210] **viXra:1607.0015 [pdf]**
*submitted on 2016-07-02 02:33:06*

**Authors:** Philip Gibbs

**Comments:** Pages. DOI: 10.13140/RG.2.2.13171.12325

Sixty years ago Richard Bellman issued a difficult challenge to his fellow mathematicians. If a rambler is lost in a forest of known shape and size, how can she find the best path to follow in order to escape as quickly as possible? So far solutions are only known for a handful of simple cases and the general problem has therefore been described as “unapproachable.” In this work a computational “random paths” method to search for optimal escape paths inside convex polygonal forests is described. In particular likely solutions covering all cases of isosceles triangles are given. Each conjectured solution provides a potentisl upper-bound for Moser’s worm problem. Surprisingly there are two cases of triangles which would provide improvements on the best known proven upper bounds.

**Category:** Geometry

[209] **viXra:1606.0253 [pdf]**
*submitted on 2016-06-24 06:43:12*

**Authors:** James A. Smith

**Comments:** 8 Pages.

This document is intended to be a convenient collection of explanations and techniques given elsewhere in the course of solving tangency problems via Geometric Algebra.

**Category:** Geometry

[208] **viXra:1606.0050 [pdf]**
*submitted on 2016-06-05 13:16:17*

**Authors:** Philip Gibbs

**Comments:** Pages. DOI: 10.13140/RG.2.2.28270.61767

Bellman’s challenge to find the shortest path to escape
from a forest of known shape is notoriously difficult. Apart from a
few of the simplest cases, there are not even many conjectures for
likely solutions let alone proofs. In this work it is shown that when
the forest is a convex polygon then at least one shortest escape path
is a piecewise curve made from segments taking the form of either
straight lines or circular arcs. The circular arcs are formed from the
envelope of three sides of the polygon touching the escape path at
three points. It is hoped that in future work these results could lead
to a practical computational algorithm for finding the shortest escape
path for any convex polygon.

**Category:** Geometry

[207] **viXra:1605.0314 [pdf]**
*submitted on 2016-05-31 21:49:03*

**Authors:** James A. Smith

**Comments:** 19 Pages.

The famous "Problem of Apollonius", in plane geometry, is to construct all of the circles that are tangent, simultaneously, to three given circles. In one variant of that problem, one of the circles has innite radius (i.e., it's a line). The Wikipedia article that's current as of this writing has an extensive description of the problem's history, and of methods that have been used to solve it. As described in that article, one of the methods reduces the "two circles and a line" variant to the so-called "Circle-Line-Point" (CLP) special case: Given a circle C, a line L, and a point P, construct the circles that are tangent to C and L, and pass through P. This document has been prepared for two very different audiences: for my fellow students of GA, and for experts who are preparing materials for us, and need to know which GA concepts we understand and apply readily, and which ones we do not.

**Category:** Geometry

[206] **viXra:1605.0233 [pdf]**
*submitted on 2016-05-22 20:06:09*

**Authors:** James A. Smith

**Comments:** 6 Pages.

The beautiful Problem of Apollonius from classical geometry (``\textit{Construct all of the circles that are tangent, simultaneously, to three given coplanar circles}") does not appear to have been solved previously by vector methods. It is solved here via GA to show students how they can make use of GA's capabilities for expressing and manipulating rotations and reflections. As Viète did when deriving his ruler-and-compass solution, we first transform the problem by shrinking one of the given circles to a point. In the course of solving the transformed problem, guidance is provided to help students ``see" geometric content in GA terms. Examples of the guidance that is given include (1) recognizing and formulating useful reflections and rotations that are present in diagrams; (2) using postulates on the equality of multivectors to obtain solvable equations; and (3) recognizing complex algebraic expressions that reduce to simple rotations of multivectors.

**Category:** Geometry

[205] **viXra:1605.0232 [pdf]**
*submitted on 2016-05-22 20:17:30*

**Authors:** James A. Smith

**Comments:** 76 Pages.

Written as somewhat of a "Schaums Outline" on the subject, which is especially useful in robotics and mechatronics. Geometric Algebra (GA) was invented in the 1800s, but was largely ignored until it was revived and expanded beginning in the 1960s. It promises to become a "universal mathematical language" for many scientific and mathematical disciplines. This document begins with a review of the geometry of angles and circles, then treats rotations in plane geometry before showing how to formulate problems in GA terms, then solve the resulting equations. The six problems treated in the document, most of which are solved in more than one way, include the special cases that Viete used to solve the general Problem of Apollonius.

**Category:** Geometry

[204] **viXra:1605.0024 [pdf]**
*submitted on 2016-05-03 01:13:07*

**Authors:** Ion Patrascu, Florentin Smarandache

**Comments:** 180 Pages.

We approach several themes of classical geometry of the circle and complete them with some original results, showing that not everything in traditional math is revealed, and that it still has an open character. The topics were chosen according to authors aspiration and attraction, as a poet writes lyrics about spring according to his emotions.

**Category:** Geometry

[203] **viXra:1604.0148 [pdf]**
*submitted on 2016-04-09 00:13:17*

**Authors:** Christopher Goddard

**Comments:** Presentation / Slidedeck, 41 pages

This slide-deck was used as a vehicle for delivery of a talk received at the Mathematics of Planet Earth conference 2013 in Melbourne. In the contents provided herein, I sketch an approach to understand and control dynamical systems that may be subject to tipping points, vis a vis catastrophe theory.

**Category:** Geometry

[202] **viXra:1602.0270 [pdf]**
*submitted on 2016-02-21 13:29:33*

**Authors:** Bogdan Szenkaryk "Pinopa"

**Comments:** 1 Page. Contact the Author - ratunek.nauki(at)onet.pl

The article comprises equation even more beautiful than Euler's identity, which is considered the most beautiful math equation. The equation is even more beautiful, because from it is derived Euler's identity. Besides, there can be derived from it many other no less beautiful mathematical identities as Euler's.

**Category:** Geometry

[201] **viXra:1602.0269 [pdf]**
*submitted on 2016-02-21 13:31:46*

**Authors:** Bogdan Szenkaryk "Pinopa"

**Comments:** 1 Page. Contact the Author - ratunek.nauki(at)onet.pl

Novelty which earlier - before it appears - no one saw; the beautiful equation.

**Category:** Geometry

[200] **viXra:1602.0252 [pdf]**
*submitted on 2016-02-20 11:33:33*

**Authors:** Robert B. Easter

**Comments:** 12 Pages.

This paper gives an overview of two different, but closely related, double conformal geometric algebras. The first is the G(8,2) Double Conformal / Darboux Cyclide Geometric Algebra (DCGA), and the second is the G(4,8) Double Conformal Space-Time Algebra (DCSTA). DCSTA is a straightforward extension of DCGA. The double conformal geometric algebras that are presented in this paper have a large set of operations that are valid on general quadric surface entities. These operations include rotation, translation, isotropic dilation, spacetime boost, anisotropic dilation, differentiation, reflection in standard entities, projection onto standard entities, and intersection with standard entities. However, the quadric surface entities and other "non-standard entities" cannot be intersected with each other.

**Category:** Geometry

[199] **viXra:1602.0249 [pdf]**
*submitted on 2016-02-20 04:32:07*

**Authors:** Orgest ZAKA, Kristaq FILIPI

**Comments:** 9 Pages.

In this paper, based on several meanings and statements discussed in the literature, we intend
constuction a affine plane about a of whatsoever corps (K,+,*). His points conceive as
ordered pairs (α,β), where α and β are elements of corps (K,+,*). Whereas straight-line in
corps, the conceptualize by equations of the type x*a+y*b=c, where a≠0K or b≠0K the
variables and coefficients are elements of that body. To achieve this construction we prove
some theorems which show that the incidence structure A=(P, L, I) connected to the corps
K satisfies axioms A1, A2, A3 definition of affine plane. In all proofs rely on the sense of the
corps as his ring and properties derived from that definition.

**Category:** Geometry

[198] **viXra:1602.0234 [pdf]**
*submitted on 2016-02-19 06:49:44*

**Authors:** Espen Gaarder Haug

**Comments:** 14 Pages.

Squaring the Circle is a famous geometry problem going all the way back to the ancient Greeks. It is the great quest of constructing a square with the same area as a circle using a compass and straightedge in a finite number of steps. Since it was proved that ⇡ was a transcendental number in 1882, the task of Squaring the Circle has been considered impossible. Here, we will show it is possible to Square the Circle in Euclidean space-time. It is not possible to Square the Circle in Euclidean space alone, but it is fully possible in Euclidean space-time, and after all we live in a world with not only space, but also time. By drawing the circle from one reference frame and drawing the square from another reference frame, we can indeed Square the Circle. By taking into account space-time rather than just space the Impossible is possible! However, it is not enough simply to understand math in order to Square the Circle, one must understand some “basic” space-time physics as well.

**Category:** Geometry

[197] **viXra:1602.0074 [pdf]**
*submitted on 2016-02-06 11:14:56*

**Authors:** editor Florentin Smarandache

**Comments:** 156 Pages.

In the new Techno-Art of Selariu SuperMathematics Functions ALBUM (the second book of Selariu SuperMathematics Functions), one contemplates a unique COMPOSITION, INTER-, INTRA- and TRANS-DISCIPLINARY. A comprehensive and savant INTRODUCTION explains the genesis of the inserted "figures", the addressees being, without discriminating criteria, equally engineers, mathematicians, artists, graphic designers, architects, and all lovers of beauty – as the love of beauty is the supreme form of love. If I should put a label on the "content" of this ALBUM, I would concoct the word NEO-BEAUTY!
The new complements of mathematics, reunited under the name of ex-centric mathematics (EM), extend (theoretically, endless) their scope; in this respect, Selariu SuperMathematics Functions are undeniable arguments! The author has labored (especially in the last three decades) extensively and fruitfully in the elitist field of the domain.
To mention some 'milestones' in this ALBUM, I choose specific mathematical elements, supermatematically hybridated: quadrilobic cubes, sphericubes, conopyramids, ex-centric spirals, severed toroids. There are also those that would qualify as "utilitarian": clepsydras, vases, baskets, lampions, or those suggestively “baptized” (by the author): butterflies, octopuses, flying saucers, jellies, roundabouts, ribands, and so on – all superlatively designed in shapes and colors! Striking phrases, such as “staggering multiplication of the dimensions of the Universe”, “integration through differential division” etc., become plausible (and explained) by replacing the time (of Einstein's four-dimensional space) with ex-centricity. Consequently, classical geometrical bodies (for e=0): the sphere, the cylinder, the cone, undergo metamorphosis (for e = +/-1), respectively into a cube, a prism, a pyramid. Inevitably and invariably, it is confirmed again that science is a finite space that grows in the infinite space; each new "expansion" does include a new area of unknown, but the unknown is inexhaustible...
Just browsing the ALBUM pages, you feel induced by the sensation of pleasure, of love at first sight; the variety of "exhibits", most of them unusual, the elegance, the symmetry of the layout, the chromatic, and so one, delight the eye, but equally incites to catchy intellectual exploration.

**Category:** Geometry

[196] **viXra:1601.0127 [pdf]**
*submitted on 2016-01-12 09:19:21*

**Authors:** Kang Yang, Kevin yang, Shuang-ren Ren Zhao

**Comments:** 13 Pages. This is one of best method to create a polygon or to solve the problem "inside the polygon"

There are many method for nding whether a point is inside a polygon or not. The congregation
of all points inside a polygon can be referred point congregation of polygon. Assume on a plane
there are N points. Assume the polygon have M vertexes. There are O(NM) calculations to create
the point congregation of polygon. Assume N>>M, we oer a parallel calculation method which
is suitable for GPU programming. Our method consider a polygon is consist of many fan regions.
The fan region can be positive and negative.
We wold like to extended this method to 3 D problem where a polyhedron instead of polygon should be drawn using cones.

**Category:** Geometry

[195] **viXra:1512.0414 [pdf]**
*submitted on 2015-12-23 16:24:57*

**Authors:** Jose Carlos Tiago de Oliveira

**Comments:** 6 Pages.

ABSTRACT
Mario Markus, a Chilean scientist and artist from Dortmund Max Planck Institute, has exposed a large set of
images of Lyapunoff exponents for the logistic equation modulated through rhythmic oscillation of parameters. The
pictures display features like foreground/background contrast, visualizing superstability, structural instability and, above
all, multistability, in a way visually analogous to three-dimensional representation.
See, for instance, http://www.mariomarkus.com/hp4.html.
The present papers aims to classify, through codification of numbers in the unit interval, the ensemble of images
thus generated. The above is intended as a part of a still unfulfilled work in progress, the classification of style in visual
fractal images-a common endeavour to Art and Science.

**Category:** Geometry

[194] **viXra:1512.0403 [pdf]**
*submitted on 2015-12-23 03:32:54*

**Authors:** Martin Erik Horn

**Comments:** 1 Page. The complete paper can be found at http://www.phydid.de (Wuppertal 2015)

An overview over all possible elementary reflections is given. It shows that a quarter of all reflections are negative.

**Category:** Geometry

[193] **viXra:1512.0303 [pdf]**
*submitted on 2015-12-13 02:52:45*

**Authors:** Robert B. Easter

**Comments:** 25 Pages.

This paper introduces the differential operators in the G(8,2) Geometric Algebra, called the Double Conformal / Darboux Cyclide Geometric Algebra (DCGA). The differential operators are three x, y, and z-direction bivector-valued differential elements and either the commutator product or the anti-commutator product for multiplication into a geometric entity that represents the function to be differentiated. The general form of a function is limited to a Darboux cyclide implicit surface function. Using the commutator product, entities representing 1st, 2nd, or 3rd order partial derivatives in x, y, and z can be produced. Using the anti-commutator product, entities representing the anti-derivation can be produced from 2-vector quadric surface and 4-vector conic section entities. An operator called the pseudo-integral is defined and has the property of raising the x, y, or z degree of a function represented by an entity, but it does not produce a true integral. The paper concludes by offering some basic relations to limited forms of vector calculus and differential equations that are limited to using Darboux cyclide implicit surface functions. An example is given of entity analysis for extracting the parameters of an ellipsoid entity using the differential operators.

**Category:** Geometry

[192] **viXra:1512.0233 [pdf]**
*submitted on 2015-12-06 05:52:26*

**Authors:** Abdelmajid Ben Hadj Salem

**Comments:** 6 Pages. In French.

In this paper, we give the equations of the geodesics of the tori and the integration of it.

**Category:** Geometry

[191] **viXra:1511.0245 [pdf]**
*submitted on 2015-11-24 16:21:26*

**Authors:** Rodolfo A. Frino

**Comments:** 7 Pages.

This paper solves the problem of the right scalene triangle through a general sequential solution. A simplified solution is also presented.

**Category:** Geometry

[190] **viXra:1511.0212 [pdf]**
*submitted on 2015-11-22 07:13:44*

**Authors:** Abdelmajid Ben Hadj Salem

**Comments:** 9 Pages. In French.

This note of differential geometry concerns the formulas of Elie Cartan about the differntial forms on a surface. We calculate these formulas for an ellipsoïd of revolution used in geodesy.

**Category:** Geometry

[189] **viXra:1511.0202 [pdf]**
*submitted on 2015-11-21 05:45:24*

**Authors:** Abdelmajid Ben Hadj Salem

**Comments:** 9 Pages. In French.

The paper concerns the Peterson operator in differentail geometry. The case of the sphere is presented as an example.

**Category:** Geometry

[188] **viXra:1511.0182 [pdf]**
*submitted on 2015-11-19 20:01:11*

**Authors:** Robert B. Easter

**Comments:** 16 Pages.

The G(8,2) Geometric Algebra, also called the Double Conformal / Darboux Cyclide Geometric Algebra (DCGA), has entities that represent conic sections. DCGA also has entities that represent planar sections of Darboux cyclides, which are called cyclidic sections in this paper. This paper presents these entities and many operations on them. Operations include reflection, projection, rejection, and intersection with respect to spheres and planes. Other operations include rotation, translation, and dilation. Possible applications are introduced that include orthographic and perspective projections of conic sections onto view planes, which may be of interest in computer graphics or other computational geometry subjects.

**Category:** Geometry

[187] **viXra:1510.0328 [pdf]**
*submitted on 2015-10-19 12:12:59*

**Authors:** Markos Georgallides

**Comments:** 67 Pages.

The Special Problems of E-geometry consist the Quantization Moulds of Euclidean Geometry in it , to become → The Basic monad , through mould of Space –Anti-space in itself , which is the material dipole in inner monad Structure as it is Electromagnetic cycloidal field → Linearly , through mould of Parallel Theorem , which are the equal distances between the points of parallel and line → In Plane , through mould of Squaring the circle , where the two equal and perpendicular monads consist a Plane acquiring the common Plane-meter → and in Space (volume) , through mould of the Duplication of the Cube , where any two Un-equal and perpendicular monads acquire the common Space-meter to be twice each other , as this in the analytical methods explained . The article consist also a provocation to all scarce today Geometers and to mathematicians in order to give an answer to this article and its content . All Geometrical solutions of the Old-age standing Unsolved Problems are now solved and are clearly Exposed , and reveal the pass-over-faults of Relativity .

**Category:** Geometry

[186] **viXra:1508.0264 [pdf]**
*submitted on 2015-08-27 02:36:17*

**Authors:** Ion Pătrașcu, Florentin Smarandache

**Comments:** 4 Pages.

În acest articol scoatem în evidență axa radicală a cercurilor Lemoine.

**Category:** Geometry

[185] **viXra:1508.0262 [pdf]**
*submitted on 2015-08-27 02:39:07*

**Authors:** Ion Pătrașcu, Florentin Smarandache

**Comments:** 5 Pages.

Laturile unui triunghi sunt împărțite de primul cerc Lemoine în segmente proporționale cu pătratele laturilor triunghiului.

**Category:** Geometry

[184] **viXra:1508.0260 [pdf]**
*submitted on 2015-08-27 02:43:09*

**Authors:** Florentin Smarandache

**Comments:** 221 Pages.

The degree of difficulties of the problems is from easy and medium to hard. The solutions of the problems are at the end of each chapter. One can navigate back and forth from the text of the problem to its solution using bookmarks. The book is especially a didactical material for the mathematical students and instructors.

**Category:** Geometry

[183] **viXra:1508.0245 [pdf]**
*submitted on 2015-08-27 03:08:22*

**Authors:** Ion Pătrașcu, Florentin Smarandache

**Comments:** 5 Pages.

The first Lemoine circle divides the sides of a triangle in segments proportional to the squares of the triangle’s sides.

**Category:** Geometry

[182] **viXra:1508.0222 [pdf]**
*submitted on 2015-08-27 03:47:56*

**Authors:** Kalyan Mondal, Surapati Pramanik

**Comments:** 10 Pages.

This paper presents rough netrosophic multiattribute decision making based on grey relational analysis. While the concept of neutrosophic sets is a powerful logic to deal with indeterminate and inconsistent data, the theory of rough neutrosophic sets is also a powerful mathematical tool to deal with incompleteness.

**Category:** Geometry

[181] **viXra:1508.0188 [pdf]**
*submitted on 2015-08-22 21:37:45*

**Authors:** Joseph I. Thomas

**Comments:** 70 Pages.

This paper consolidates all the salient geometrical aspects of the principle of Polychronous Wavefront Computation. A novel set of simple and closed planar curves are constructed based on this principle, using MATLAB. The algebraic and geometric properties of these curves are then elucidated as theorems, propositions and conjectures.

**Category:** Geometry

[180] **viXra:1508.0154 [pdf]**
*submitted on 2015-08-19 20:44:14*

**Authors:** Ben Steber

**Comments:** 4 Pages.

The author will demonstrate that the sums of odd numbers to an nth value equals that nth value squared. A geometric proof will be provided to demonstrate the principle of sum odds equaling squares.

**Category:** Geometry

[179] **viXra:1508.0086 [pdf]**
*submitted on 2015-08-11 10:39:32*

**Authors:** Robert B. Easter

**Comments:** 43 Pages.

This paper introduces the Double Conformal Geometric Algebra (DCGA), based in the G8,2 Clifford geometric algebra. DCGA is an extension of CGA and adds geometrical entities for all 3D quadric surfaces and a toroid entity. All entities, representing various geometric surfaces and points, can be transformed in 3D space by rotors, dilators, translators, and motors, which are all types of versors. Versors provide an algebra of spatial transformations that are different than linear algebra transformations. Entities representing the intersections of geometric surfaces can also be created by wedge products. DCGA provides a higher-level algebra for working with 3D geometry in an object/entity-oriented system of mathematics above the level of the underlying homogeneous polynomial equations of algebraic geometry. DCGA could be used in the study of geometry in 3D, and also for some applications.

**Category:** Geometry

[178] **viXra:1507.0218 [pdf]**
*submitted on 2015-07-29 23:15:12*

**Authors:** Dao Thanh Oai

**Comments:** 3 Pages.

In this note, I introduce three conjectures of generalization of the Lester circle theorem, the Parry circle theorem, the Zeeman-Gossard perspector theorem respectively

**Category:** Geometry

[177] **viXra:1507.0216 [pdf]**
*submitted on 2015-07-29 05:10:57*

**Authors:** Dao Thanh Oai

**Comments:** 1 Page.

In Euclidean geometry, Feuerbach-Luchterhand theorem is a generalization of Pythagorean
theorem, Stewart theorem and the British Flag theorem.....In this note, I propose two
conjectures of generalization of Feuerbach-Luchterhand theorem.

**Category:** Geometry

[176] **viXra:1504.0189 [pdf]**
*submitted on 2015-04-24 03:39:05*

**Authors:** S.Kalimuthu

**Comments:** 4 Pages. If there is a flaw in the proof, I welcome it.Thank you.

Reputed Austrian American mathematician Kurt Gödel formulated two extraordinary propositions in mathematical lo0gic.Accepted by all mathematicians they have revolutionized mathematics, showing that mathematical truth is more than logic and computation. These two ground breaking theorems changed mathematics, logic, and even the way we look at our Universe. The cognitive scientist Douglas Hofstadter described Gödel’s first incompleteness theorem as that in a formal axiomatic mathematical system there are propositions that can neither be proven nor disproven. The logician and mathematician Jean van Heijenoort summarizes that there are formulas that are neither provable nor disprovable. According to Peter Suber, inn a formal mathematical system, there are un decidable statements. S. M. Srivatsava formulates that formulations of number theory include undecidable propositions. And Miles Mathis describes Gödel’s first incompleteness theorem as that in a formal axiomatic mathematical system we can construct a statement which is neither true nor false. [Mathematical variance of liar’s paradox]In this short work, the author attempts to show these equivalent propositions to Gödel’s incompleteness theorems by applying elementary arithmetic operations, algebra and hyperbolic geometry. [1 – 6 ]

**Category:** Geometry

[175] **viXra:1504.0085 [pdf]**
*submitted on 2015-04-10 10:51:29*

**Authors:** Wenceslao Segura González

**Comments:** 126 Pages. Book. Spanish

Este es un libro de Matemática para físicos. Con ello queremos decir que los conceptos y desarrollos matemáticos que exponemos se hacen con la finalidad de aplicarlos a la Física; o sea, aquí entendemos la Matemática como una herramienta, y como tal herramienta no es importante el grado de rigor con la que se aplique, sino la utilidad que se consiga en el desarrollo de las teorías físicas.
Por esta razón hemos huido de un excesivo rigor, lo que tal vez sea del desagrado del matemático, pero que tenemos la seguridad de que agradará al físico.
Hemos titulado el libro «La conexión afín» para recalcar que este es el concepto básico de la geometría diferencial en cuanto a su aplicación a la teoría clásica de campo.
Los resultados matemáticos que recopilamos en el primer capítulo son aplicados a la formulación de las ecuaciones de la Relatividad General y a teorías unitarias de campo, siempre dentro de la visión clásica.
La generalización de la Relatividad General, ya sea en orden a su unificación con el electromagnetismo o a la búsqueda de nuevas teorías gravitatorias, ha recuperado interés recientemente y esta es la razón principal de que publiquemos este opúsculo.
ISBN: 978-84-606-7167-1

**Category:** Geometry

[174] **viXra:1502.0244 [pdf]**
*submitted on 2015-02-28 02:10:48*

**Authors:** Gerasimos T. Soldatos

**Comments:** 16 Pages.

The problems of squaring the circle or “quadrature” and trisection of an acute angle are supposed to be impossible to solve because the geometric constructibility, i.e. compass-and-straightedge construction, of irrational numbers like π is involved, and such numbers are not constructible. So, if these two problems were actually solved, it would imply that irrational numbers are geometrically constructible and this, in turn, that the infinite of the decimal digits of such numbers has an end, because it is this infinite which inhibits constructibility. A finitely infinite number of decimal digits would be the case if the infinity was the actual rather than the potential one. Euclid's theorem rules out the presence of actual infinity in favor of the infinite infinity of the potential infinity. But, space per se is finite even if it is expanding all the time, casting consequently doubt about the empirical relevance of this theorem in so far as the nexus space-actual infinity is concerned. Assuming that the quadrature and the trisection are space only problems, they should subsequently be possible to solve, prompting, in turn, a consideration of the real-world relevance of Euclid's theorem and of irrationality in connection with time and spacetime and hence, motion rather than space alone. The number-computability constraint suggests that only logically, i.e. through Euclidean geometry, this issue can be dealt with. So long as any number is expressible as a polynomial root the issue at hand boils down to the geometric constructibility of any root. This article is an attempt towards this direction after having tackled the problems of quadrature and trisection first by themselves through reductio ad impossibile in the form of proof by contradiction, and then as two only examples of the general problem of polynomial root construction. The general conclusion is that an irrational numbers is irrational on the real plane, but in the three-dimensional world, it is as a vector the image of one at least constructible position vector, and through the angle formed between them, constructible becomes the “irrational vector” too, as a right-triangle side. So, the physical, the real-world reflection of the impossibility of quadrature and trisection should be sought in connection with spacetime, motion, and potential infinity.

**Category:** Geometry

[173] **viXra:1502.0093 [pdf]**
*submitted on 2015-02-12 15:14:04*

**Authors:** Sidharth Ghoshal

**Comments:** 5 Pages.

Derivation of a technique of determining distances from spherical cameras. Can be generalized to more complex surfaces

**Category:** Geometry

[172] **viXra:1502.0061 [pdf]**
*submitted on 2015-02-08 14:38:03*

**Authors:** Florentin Smarandache

**Comments:** 177 Pages.

Acest volum este o versiune nouă, revizuită și adăugită, a "Problemelor Compilate şi Rezolvate de Geometrie şi Trigonometrie" (Universitatea din Moldova, Chișinău, 169 p., 1998), și include
probleme de geometrie și trigonometrie, compilate și soluționate în perioada 1981-1988, când profesam matematica la Colegiul Național "Petrache Poenaru" din Bălcești, Vâlcea (Romania), la Lycée Sidi El Hassan Lyoussi din Sefrou (Maroc), apoi la Colegiul Național "Nicolae Balcescu" din Craiova. Gradul de dificultate al problemelor este de la usor si mediu spre greu. Cartea se dorește material didactic pentru elevi, studenți și profesori.

**Category:** Geometry

[171] **viXra:1502.0026 [pdf]**
*submitted on 2015-02-03 22:21:45*

**Authors:** Florentin Smarandache

**Comments:** 219 Pages.

This book is a translation from Romanian of "Probleme Compilate şi Rezolvate de Geometrie şi Trigonometrie" (University of Kishinev Press, Kishinev, 169 p., 1998), and includes 255 problems of 2D and 3D Euclidean geometry plus trigonometry, compiled and solved from the Romanian Textbooks for 9th and 10th grade students, in the period 1981-1988, when I was a professor of mathematics at the "Petrache Poenaru" National College in Balcesti, Valcea (Romania), Lycée Sidi El Hassan Lyoussi in Sefrou (Morocco), then at the "Nicolae Balcescu" National College in Craiova and Dragotesti General School (Romania), but also I did intensive private tutoring for students preparing their university entrance examination. After that, I have escaped in Turkey in September 1988 and lived in a political refugee camp in Istanbul and Ankara, and in March 1990 I immigrated to United States. The degree of difficulties of the problems is from easy and medium to hard. The solutions of the problems are at the end of each chapter. One can navigate back and forth from the text of the problem to its solution using bookmarks. The book is especially a didactic material for the mathematical students and instructors.

**Category:** Geometry

[170] **viXra:1502.0006 [pdf]**
*submitted on 2015-02-01 07:51:15*

**Authors:** Joseph I. Thomas

**Comments:** 10 Pages.

Two circles C(O,r) and C(O',r'), expanding at an equal and uniform rate in a plane, come to intersect each other in a branch of a hyperbola, referred to here as a dynamic hyperbola.
In this paper, the analytical equation of the dynamic hyperbola is derived in a step by step fashion. Also, three of its immediate applications, into neuroscience, engineering and physics, respectively is summarized at the end.

**Category:** Geometry

[169] **viXra:1411.0362 [pdf]**
*submitted on 2014-11-19 03:58:28*

**Authors:** Eckhard Hitzer

**Comments:** 10 Pages. Submitted to Proceedings of the 30th International Colloquium on Group Theoretical Methods in Physics (troup30), 14-18 July 2014, Ghent, Belgium, to be published by IOP in the Journal of Physics: Conference Series (JPCS), 2014.

Recently the general orthogonal planes split with respect to any two pure unit quaternions $f,g \in \mathbb{H}$, $f^2=g^2=-1$, including the case $f=g$, has proved extremely useful for the construction and geometric interpretation of general classes of double-kernel quaternion Fourier transformations (QFT) [E.Hitzer, S.J. Sangwine, The orthogonal 2D planes split of quaternions and steerable quaternion Fourier Transforms, in E. Hitzer, S.J. Sangwine (eds.), "Quaternion and Clifford Fourier Transforms and Wavelets", TIM \textbf{27}, Birkhauser, Basel, 2013, 15--39.].
Applications include color image processing, where the orthogonal planes split with $f=g=$ the grayline, naturally splits a pure quaternionic three-dimensional color signal into luminance and chrominance components. Yet it is found independently in the quaternion geometry of rotations [L. Meister, H. Schaeben, A concise quaternon geometry of rotations, MMAS 2005; \textbf{28}: 101--126],
that the pure quaternion units $f,g$ and the analysis planes, which they define, play a key role in the spherical geometry of rotations, and the geometrical interpretation of integrals related to the spherical Radon transform of probability density functions of unit quaternions, as relevant for texture analysis in crystallography. In our contribution we further investigate these connections.

**Category:** Geometry

[168] **viXra:1411.0143 [pdf]**
*submitted on 2014-11-14 17:04:01*

**Authors:** J Gregory Moxness

**Comments:** 10 Pages.

This paper will present various techniques for visualizing a split real even $E_8$ representation in 2 and 3 dimensions using an $E_8$ to $H_4$ folding matrix. This matrix is shown to be useful in providing direct relationships between $E_8$ and the lower dimensional Dynkin and Coxeter-Dynkin geometries contained within it, geometries that are visualized in the form of real and virtual 3 dimensional objects.

**Category:** Geometry

[167] **viXra:1411.0038 [pdf]**
*submitted on 2014-11-05 08:23:18*

**Authors:** Philip Gibbs

**Comments:** 5 Pages.

The moving sofa problem seeks the shape of largest area that can be moved round an L-shaped corner in a corridor of width one. A geometric computation is performed giving a result which is indistinguishable by eye from Gerver's proposed solution of 1992. The computed area also agrees to nearly eight significant figures.

**Category:** Geometry

[166] **viXra:1410.0160 [pdf]**
*submitted on 2014-10-26 07:08:02*

**Authors:** Wenceslao Segura González

**Comments:** 35 Pages. Spanish

The affine connection is the primary geometric element from which derive all other quantities that characterize a given geometry. In this article the concept of affine connection, its properties and the quantities derived from it are studied, we also present some of the connections that have been used in physical theories. We introduce the metric tensor and we study its relation with the affine connection. This study is intended for application in alternative theories of gravity to the General Theory of Relativity and to the unified field theories.

**Category:** Geometry

[165] **viXra:1410.0139 [pdf]**
*submitted on 2014-10-22 19:49:20*

**Authors:** Linfan MAO

**Comments:** 25 Pages.

As we known, an objective thing not moves
with one's volition, which implies that all contradictions,
particularly, in these semiotic systems for things are artificial.
In classical view, a contradictory system is meaningless, contrast
to that of geometry on figures of things catched by eyes of human
beings. The main objective of sciences is holding the global
behavior of things, which needs one knowing both of compatible and
contradictory systems on things. Usually, a mathematical system
including contradictions is said to be a {\it Smarandache system}.
Beginning from a famous fable, i.e., the $6$ blind men with an
elephant, this report shows the geometry on contradictory systems,
including non-solvable algebraic linear or homogenous equations,
non-solvable ordinary differential equations and non-solvable
partial differential equations, classify such systems and
characterize their global behaviors by combinatorial geometry,
particularly, the global stability of non-solvable differential
equations. Applications of such systems to other sciences, such as
those of gravitational fields, ecologically industrial systems can
be also found in this report. All of these discussions show that a
non-solvable system is nothing else but a system underlying a
topological graph $G\not\simeq K_n$, or $\simeq K_n$ without common
intersection, contrast to those of solvable systems underlying $K_n$
being with common non-empty intersections, where $n$ is the number
of equations in this system. However, if we stand on a geometrical
viewpoint, they are compatible and both of them are meaningful for
human beings.

**Category:** Geometry

[164] **viXra:1409.0077 [pdf]**
*submitted on 2014-09-11 10:00:26*

**Authors:** Hanno Essén, Lars Hörnfeldt

**Comments:** 1 Page. Abstracts of contributed papers, 11th international conference on general relativity and gravitation, Stockholm, Sweden, abstract no 1:12 (supplementary volume), July 6-12 1986

The curvature tensor and scalar is computed for n up to 6 with the computer algebra system STENSOR. From that new empircal material, formulae for any n are deduced. For the special case of a sphere they coincide with wellknown results.

**Category:** Geometry

[163] **viXra:1409.0026 [pdf]**
*submitted on 2014-09-04 13:59:38*

**Authors:** Jan Hakenberg

**Comments:** 50 Pages.

Simple meshes such as the cube, tetrahedron, and tripod frequently appear in the literature to illustrate the concept of subdivision. The formulas for the volume, centroid, and inertia of the sets bounded by subdivision surfaces have only recently been derived. We specify simple meshes and state the moments of degree 0 and 1 defined by the corresponding limit surfaces. We consider the subdivision schemes Doo-Sabin, Loop, and Loop with sharp creases.

In case of Doo-Sabin, the moment of degree 2 is also available for certain simple meshes. The inertia is computed and visualized with respect to the centroid.

[162] **viXra:1409.0022 [pdf]**
*submitted on 2014-09-04 02:09:40*

**Authors:** Joseph I. Thomas

**Comments:** 10 Pages.

Trilateration is the name given to the Algorithm used in Global Positioning System (GPS) technology to localize the position of a Transmitter/Receiver station (also called a Blind Node) in a 2D plane, using the positional knowledge of three non-linearly placed Anchor Nodes. For instance, it may be desired to locate the whereabouts of a mobile phone (Blind Node) lying somewhere within the range of three radio signal transmitting towers (Anchor Nodes). There are various Trilateration Algorithms in the literature that achieve this end using among other methods, linear algebra.
This paper is a direct spin off from prior work by the same author, titled “A Mathematical Treatise on Polychronous Wavefront Computation and its Applications into Modeling Neurosensory Systems”. The Geometric Algorithm developed there was originally intended to localize the position of a special class of neurons called Coincidence Detectors in the Central Neural Field. A general outline of how the same methodology can be adapted for the purpose of Trilateration, is presented here.

**Category:** Geometry

[161] **viXra:1408.0200 [pdf]**
*submitted on 2014-08-28 16:04:49*

**Authors:** Tobías de Jesús Rosas Soto

**Comments:** 16 Pages. Artículo en español, con resumen en inglés. Contiene ecuaciones, y 8 figuras, a color para mejor comprensión.

Se presenta el estudio de propiedades geométricas de un cuadrilátero inscrito en una circunferencia, en un plano de Minkowski. Se estudian las relaciones entre los cuatro triángulos formados por los vértices del cuadrilátero, sus antitriángulos y puntos de simetría, sus baricentros y otros puntos asociados con dichos triángulos, respectivamente. Se introduce la noción de anticuadrilátero y se extiende la noción de circunferencia de Feuerbach de un cuadriláteros, inscritos en una circunferencia, a planos de Minkowski en general.
---
The study of geometric properties of a inscribed quadrangle in a circle, in a Minkowski plane is presented. We study the relations between the four triangles formed by the vertices of the quadrangle, its anti-triangles and points of symmetry, its barycenters and other points associated with such triangles, respectively. The notion of anti-quadrangle is introduced and extends the notion of Feuerbach circle for quadrangles, inscribed in a circle, to Minkowski planes in general.

**Category:** Geometry

[160] **viXra:1408.0191 [pdf]**
*submitted on 2014-08-27 22:59:49*

**Authors:** Tobías de Jesús Rosas Soto

**Comments:** 17 Pages. Artículo en español, con resumen en inglés. Contiene ecuaciones, y 13 figuras, a color para mejor comprensión.

Usando la noción de C-ortocentro se extienden, a planos de Minkowski en general, nociones de la geometría clásica relacionadas con un triángulo, como por ejemplo: puntos de Euler, triángulo de Euler, puntos de Poncelet. Se muestran propiedades de estas nociones y sus relaciones con la circunferencia de Feuerbach. Se estudian sistemas C-ortocéntricos formados por puntos presentes en dichas nociones y se establecen relaciones con la ortogonalidad isósceles y cordal. Además, se prueba que la imagen homotética de un sistema C-ortocéntrico es un sistema C-ortocéntrico.
--
Using the notion of C-orthocenter, notions of the classic euclidean geometry related with a triangle, as for example: Euler points; Euler’s triangle; and Poncelet’s points, are extended to Minkowski planes in general. Properties of these notions and their relations with the Feuerbach’s circle, are shown. C-orthocentric systems formed by points in the above notions are studied and relations with the isosceles and chordal orthogonality, are established. In addition, there is proved that the homothetic image of a C-orthocentric system is a C-orthocentric system.

**Category:** Geometry

[159] **viXra:1408.0143 [pdf]**
*submitted on 2014-08-22 00:31:22*

**Authors:** Tobías de Jesús Rosas Soto

**Comments:** 17 Pages. Artículo en español, con 4 figuras presentadas de a pares. Título y resumen en español e ingles.

Mediante el estudio de ciertas propiedades geométricas de los sistemas C-ortocéntricos, relacionadas co las nociones de ortogonalidad (Birkhoff, isósceles, cordal), bisectriz (Busemann, Glogovskij) y línea soporte a una circunferencia, se muestran nueve caracterizaciones de euclidianidad para planos de Minkowski arbitrarios. Tres de estas generalizan caracterizaciones dadas para planos de Minkowski estrictamente convexos en [8, 9], y las otras seis son nuevos aportes sobre el tema.
--
By studying certain geometric properties of C-orthocentric systems related to the notions of orthogonality (Birkhoff, isosceles, chordal), angular bisectors (Busemann, Glogovskij) and support line to a circumference, shows nine characterizations of the Euclidean plane for arbitrary Minkowski planes. Three of these generalized characterizations given for strictly convex Minkowski planes in [8, 9], and the other six are new contributions on subject.

**Category:** Geometry

[80] **viXra:1608.0328 [pdf]**
*replaced on 2016-08-27 23:19:26*

**Authors:** James A. Smith

**Comments:** 38 Pages.

This document adds to the collection of solved problems presented in References [1]-[6]. The solutions presented herein are not as efficient as those in [6], but they give additional insight into ways in which GA can be used to solve this problem. After reviewing, briefly, how reflections and rotations can be expressed and manipulated via GA, it solves the CLP limiting case of the Problem of Apollonius in three ways, some of which identify the the solution circles' points of tangency with the given circle, and others of which identify the solution circles' points of tangency with the given line. For comparison, the solutions that were developed in [1] are presented in an Appendix.

**Category:** Geometry

[79] **viXra:1607.0166 [pdf]**
*replaced on 2016-07-26 09:29:46*

**Authors:** James A. Smith

**Comments:** Pages.

This document adds to the collection of solved problems presented in References 1-4. After reviewing, briefly, how reflections and rotations can be expressed and manipulated via GA, it solves the LLP limiting case of the Problem of Apollonius in three ways.

**Category:** Geometry

[78] **viXra:1605.0314 [pdf]**
*replaced on 2016-08-20 22:58:10*

**Authors:** James A. Smith

**Comments:** 22 Pages.

NOTE: A new Appendix presents alternative solutions.
The famous "Problem of Apollonius", in plane geometry, is to construct all of the circles that are tangent, simultaneously, to three given circles. In one variant of that problem, one of the circles has innite radius (i.e., it's a line). The Wikipedia article that's current as of this writing has an extensive description of the problem's history, and of methods that have been used to solve it. As described in that article, one of the methods reduces the "two circles and a line" variant to the so-called "Circle-Line-Point" (CLP) special case: Given a circle C, a line L, and a point P, construct the circles that are tangent to C and L, and pass through P. This document has been prepared for two very different audiences: for my fellow students of GA, and for experts who are preparing materials for us, and need to know which GA concepts we understand and apply readily, and which ones we do not.

**Category:** Geometry

[77] **viXra:1605.0233 [pdf]**
*replaced on 2016-08-20 21:29:55*

**Authors:** James A. Smith

**Comments:** 18 Pages.

Note: The Appendix to this new version gives an alternate--and much simpler--solution that does not use reflections.
The beautiful Problem of Apollonius from classical geometry ("Construct all of the circles that are tangent, simultaneously, to three given coplanar circles") does not appear to have been solved previously by vector methods. It is solved here via Geometric Algebra (GA, also known as Clifford Algebra) to show students how they can make use of GA's capabilities for expressing and manipulating rotations and reflections. As Viète did when deriving his ruler-and-compass solution, we first transform the problem by shrinking one of the given circles to a point. In the course of solving the transformed problem, guidance is provided to help students ``see" geometric content in GA terms. Examples of the guidance that is given include (1) recognizing and formulating useful reflections and rotations that are present in diagrams; (2) using postulates on the equality of multivectors to obtain solvable equations; and (3) recognizing complex algebraic expressions that reduce to simple rotations of multivectors.
As an aid to students, the author has prepared a dynamic-geometry construction to accompany this article.

**Category:** Geometry

[76] **viXra:1605.0233 [pdf]**
*replaced on 2016-06-11 07:43:18*

**Authors:** James A. Smith

**Comments:** 15 Pages.

The beautiful Problem of Apollonius from classical geometry ("Construct all of the circles that are tangent, simultaneously, to three given coplanar circles") does not appear to have been solved previously by vector methods. It is solved here via Geometric Algebra (GA, also known as Clifford Algebra) to show students how they can make use of GA's capabilities for expressing and manipulating rotations and reflections. As Viète did when deriving his ruler-and-compass solution, we first transform the problem by shrinking one of the given circles to a point. In the course of solving the transformed problem, guidance is provided to help students ``see" geometric content in GA terms. Examples of the guidance that is given include (1) recognizing and formulating useful reflections and rotations that are present in diagrams; (2) using postulates on the equality of multivectors to obtain solvable equations; and (3) recognizing complex algebraic expressions that reduce to simple rotations of multivectors.

**Category:** Geometry

[75] **viXra:1605.0233 [pdf]**
*replaced on 2016-06-05 15:58:39*

**Authors:** James A. Smith

**Comments:** 15 Pages.

The beautiful Problem of Apollonius from classical geometry ("Construct all of the circles that are tangent, simultaneously, to three given coplanar circles") does not appear to have been solved previously by vector methods. It is solved here via Geometric Algebra (GA, also known as Clifford Algebra) to show students how they can make use of GA's capabilities for expressing and manipulating rotations and reflections. As Viète did when deriving his ruler-and-compass solution, we first transform the problem by shrinking one of the given circles to a point. In the course of solving the transformed problem, guidance is provided to help students ``see" geometric content in GA terms. Examples of the guidance that is given include (1) recognizing and formulating useful reflections and rotations that are present in diagrams; (2) using postulates on the equality of multivectors to obtain solvable equations; and (3) recognizing complex algebraic expressions that reduce to simple rotations of multivectors.

**Category:** Geometry

[74] **viXra:1605.0233 [pdf]**
*replaced on 2016-06-03 19:48:48*

**Authors:** James A. Smith

**Comments:** 14 Pages.

The beautiful Problem of Apollonius from classical geometry (“Construct all of the circles that are tangent, simultaneously, to three given coplanar circles”) does not appear to have been solved previously by vector methods. It is solved here via GA to show students how they can make use of GA’s capabilities for expressing and manipulating rotations and reflections. As Viete did when deriving his ruler-and-compass solution, we first transform the problem by shrinking one of the given circles to a point. In the course of solving
the transformed problem, guidance is provided to help students “see” geometric content in GA terms. Examples of the guidance that is given include (1) recognizing and formulating useful reflections and rotations that are present in diagrams; (2) using postulates on the equality of multivectors to obtain solvable equations; and (3)recognizing complex algebraic expressions that reduce to simple rotations of multivectors.

**Category:** Geometry

[73] **viXra:1602.0234 [pdf]**
*replaced on 2016-03-08 16:32:26*

**Authors:** Espen Gaarder Haug

**Comments:** 19 Pages.

Squaring the Circle is a famous geometry problem going all the way back to the ancient Greeks. It is the great quest of constructing a square with the same area as a circle using a compass and straightedge in a finite number of steps. Since it was proved that pi was a transcendental number in 1882, the task of Squaring the Circle has been considered impossible. Here, we will show it is possible to Square the Circle in Euclidean space-time. It is not possible to Square the Circle in Euclidean space alone, but it is fully possible in Euclidean space-time, and after all we live in a world with not only space, but also time. By drawing the circle from one reference frame and drawing the square from another reference frame, we can indeed Square the Circle. By taking into account space-time rather than just space the Impossible is possible! However, it is not enough simply to understand math in order to Square the Circle, one must understand some “basic” space-time physics as well. As a bonus we have added a solution to the impossibility of Doubling the Cube. As a double bonus we also have also boxed the sphere! As one will see one can claim we simply have bent the rules and moved a problem from one place to another. One of the main essences of this paper is that we can move challenging space problems out from space and into time, and vice versa.

**Category:** Geometry

[72] **viXra:1602.0234 [pdf]**
*replaced on 2016-02-24 04:24:44*

**Authors:** Espen Gaarder Haug

**Comments:** 17 Pages.

Squaring the Circle is a famous geometry problem going all the way back to the ancient Greeks. It is the great quest of constructing a square with the same area as a circle using a compass and straightedge in a finite number of steps. Since it was proved that pi was a transcendental number in 1882, the task of Squaring the Circle has been considered impossible. Here, we will show it is possible to Square the Circle in Euclidean space-time. It is not possible to Square the Circle in Euclidean space alone, but it is fully possible in Euclidean space-time, and after all we live in a world with not only space, but also time. By drawing the circle from one reference frame and drawing the square from another reference frame, we can indeed Square the Circle. By taking into account space-time rather than just space the Impossible is possible! However, it is not enough simply to understand math in order to Square the Circle, one must understand some “basic” space-time physics as well. As a bonus we have added a solution to the impossibility of Doubling the Cube. As a double bonus we also have also boxed the sphere! As one will see one can claim we simply have bent the rules and moved a problem from one place to another. One of the main essences of this paper is that we can move challenging space problems out from space and into time, and vice versa.

**Category:** Geometry

[71] **viXra:1602.0234 [pdf]**
*replaced on 2016-02-22 17:51:04*

**Authors:** Espen Gaarder Haug

**Comments:** 16 Pages.

Squaring the Circle is a famous geometry problem going all the way back to the ancient Greeks. It is the great quest of constructing a square with the same area as a circle using a compass and straightedge in a finite number of steps. Since it was proved that pi was a transcendental number in 1882, the task of Squaring the Circle has been considered impossible. Here, we will show it is possible to Square the Circle in Euclidean space-time. It is not possible to Square the Circle in Euclidean space alone, but it is fully possible in Euclidean space-time, and after all we live in a world with not only space, but also time. By drawing the circle from one reference frame and drawing the square from another reference frame, we can indeed Square the Circle. By taking into account space-time rather than just space the Impossible is possible! However, it is not enough simply to understand math in order to Square the Circle, one must understand some “basic” space-time physics as well. As a bonus we have added a solution to the impossibility of Doubling the Cube. As a double bonus we also have tried to box the sphere!

**Category:** Geometry

[70] **viXra:1512.0303 [pdf]**
*replaced on 2015-12-18 20:37:40*

**Authors:** Robert B. Easter

**Comments:** 30 Pages.

This paper introduces the differential operators in the G(8,2) Geometric Algebra, called the Double Conformal / Darboux Cyclide Geometric Algebra (DCGA). The differential operators are three x, y, and z-direction bivector-valued differential elements and either the commutator product or the anti-commutator product for multiplication into a geometric entity that represents the function to be differentiated. The general form of a function is limited to a Darboux cyclide implicit surface function. Using the commutator product, entities representing 1st, 2nd, or 3rd order partial derivatives in x, y, and z can be produced. Using the anti-commutator product, entities representing the anti-derivation can be produced from 2-vector quadric surface and 4-vector conic section entities. An operator called the pseudo-integral is defined and has the property of raising the x, y, or z degree of a function represented by an entity, but it does not produce a true integral. The paper concludes by offering some basic relations to limited forms of vector calculus and differential equations that are limited to using Darboux cyclide implicit surface functions. An example is given of entity analysis for extracting the parameters of an ellipsoid entity using the differential operators.

**Category:** Geometry

[69] **viXra:1512.0303 [pdf]**
*replaced on 2015-12-18 01:51:12*

**Authors:** Robert B. Easter

**Comments:** 28 Pages.

This paper introduces the differential operators in the G(8,2) Geometric Algebra, called the Double Conformal / Darboux Cyclide Geometric Algebra (DCGA). The differential operators are three x, y, and z-direction bivector-valued differential elements and either the commutator product or the anti-commutator product for multiplication into a geometric entity that represents the function to be differentiated. The general form of a function is limited to a Darboux cyclide implicit surface function. Using the commutator product, entities representing 1st, 2nd, or 3rd order partial derivatives in x, y, and z can be produced. Using the anti-commutator product, entities representing the anti-derivation can be produced from 2-vector quadric surface and 4-vector conic section entities. An operator called the pseudo-integral is defined and has the property of raising the x, y, or z degree of a function represented by an entity, but it does not produce a true integral. The paper concludes by offering some basic relations to limited forms of vector calculus and differential equations that are limited to using Darboux cyclide implicit surface functions. An example is given of entity analysis for extracting the parameters of an ellipsoid entity using the differential operators.

**Category:** Geometry

[68] **viXra:1512.0303 [pdf]**
*replaced on 2015-12-16 23:13:56*

**Authors:** Robert B. Easter

**Comments:** 28 Pages.

**Category:** Geometry

[67] **viXra:1511.0182 [pdf]**
*replaced on 2016-07-22 09:22:40*

**Authors:** Robert B. Easter

**Comments:** 16 Pages.

The G(8,2) Geometric Algebra, also called the Double Conformal / Darboux Cyclide Geometric Algebra (DCGA), has entities that represent conic sections. DCGA also has entities that represent planar sections of Darboux cyclides, which are called cyclidic sections in this paper. This paper presents these entities and many operations on them. Operations include reflection, projection, rejection, and intersection with respect to spheres and planes. Other operations include rotation, translation, and dilation. Possible applications are introduced that include orthographic and perspective projections of conic sections onto view planes, which may be of interest in computer graphics or other computational geometry subjects.

**Category:** Geometry

[66] **viXra:1508.0086 [pdf]**
*replaced on 2015-10-01 17:57:21*

**Authors:** Robert B. Easter

**Comments:** 62 Pages.

This paper introduces the Double Conformal / Darboux Cyclide Geometric Algebra (DCGA), based in the G8,2 Clifford geometric algebra. DCGA is an extension of CGA and has entities representing points and general Darboux cyclide surfaces in Euclidean 3D space. The general Darboux cyclide is a quartic surface. Darboux cyclides include circular tori and all quadrics, and also all surfaces formed by their inversions in spheres. Dupin cyclide surfaces can be formed as inversions in spheres of circular toroid, cylinder, and cone surfaces. Parabolic cyclides are cubic surfaces formed by inversion spheres centered on other surfaces. All DCGA entities can be conformally transformed in 3D space by rotors, dilators, translators, and motors, which are all types of versors. All entities can be inversed in general spheres and reflected in general planes. Entities representing the intersections of surfaces can be created by wedge products. All entities can be intersected with spheres, planes, lines, and circles. DCGA provides a higher-level algebra for working with 3D geometry in an object/entity-oriented system of mathematics above the level of the underlying implicit surface equations of algebraic geometry. DCGA could be used in the study of geometry in 3D, and also for some applications.

**Category:** Geometry

[65] **viXra:1508.0086 [pdf]**
*replaced on 2015-09-30 22:19:24*

**Authors:** Robert B. Easter

**Comments:** 62 Pages.

This paper introduces the Double Conformal / Darboux Cyclide Geometric Algebra (DCGA), based in the G8,2 Clifford geometric algebra. DCGA is an extension of CGA and has entities representing points and general Darboux cyclide surfaces in Euclidean 3D space. The general Darboux cyclide is a quartic surface. Darboux cyclides include circular tori and all quadrics, and also all surfaces formed by their inversions in spheres. Dupin cyclide surfaces can be formed as inversions in spheres of circular toroid, cylinder, and cone surfaces. Parabolic cyclides are cubic surfaces formed by inversion spheres centered on other surfaces. All DCGA entities can be conformally transformed in 3D space by rotors, dilators, translators, and motors, which are all types of versors. All entities can be inversed in general spheres and reflected in general planes. Entities representing the intersections of surfaces can be created by wedge products. All entities can be intersected with spheres, planes, lines, and circles. DCGA provides a higher-level algebra for working with 3D geometry in an object/entity-oriented system of mathematics above the level of the underlying implicit surface equations of algebraic geometry. DCGA could be used in the study of geometry in 3D, and also for some applications.

**Category:** Geometry

[64] **viXra:1508.0086 [pdf]**
*replaced on 2015-09-24 13:06:54*

**Authors:** Robert B. Easter

**Comments:** 53 Pages.

This paper introduces the Double Conformal / Darboux Cyclide Geometric Algebra (DCGA), based in the G8,2 Clifford geometric algebra. DCGA is an extension of CGA and has entities representing points and general Darboux cyclide surfaces in Euclidean 3D space. The general Darboux cyclide is a quartic surface. Darboux cyclides include circular tori and all quadrics, and also all surfaces formed by their inversions in spheres. Dupin cyclide surfaces can be formed as inversions in spheres of circular toroid, cylinder, and cone surfaces. Parabolic cyclides are cubic surfaces formed by inversion spheres centered on other surfaces. All DCGA entities can be conformally transformed in 3D space by rotors, dilators, translators, and motors, which are all types of versors. All entities can be inversed in general spheres and reflected in general planes. Entities representing the intersections of surfaces can be created by wedge products. All entities can be intersected with spheres, planes, lines, and circles. DCGA provides a higher-level algebra for working with 3D geometry in an object/entity-oriented system of mathematics above the level of the underlying implicit surface equations of algebraic geometry. DCGA could be used in the study of geometry in 3D, and also for some applications.

**Category:** Geometry

[63] **viXra:1508.0086 [pdf]**
*replaced on 2015-09-20 08:27:38*

**Authors:** Robert B. Easter

**Comments:** 52 Pages.

**Category:** Geometry

[62] **viXra:1508.0086 [pdf]**
*replaced on 2015-09-02 15:26:57*

**Authors:** Robert B. Easter

**Comments:** 49 Pages.

This paper introduces the Double Conformal Geometric Algebra (DCGA), based in the G8,2 Clifford geometric algebra. DCGA is an extension of CGA that adds geometrical entities for all 3D quadric surfaces and a torus surface. More generally, DCGA has an entity for general cyclide surfaces in 3D, which is a class of quartic surfaces that includes the quadric surfaces and toroid and also their inversions in spheres known as Dupin cyclides. All entities representing various geometric surfaces and points can be transformed in 3D space by rotors, dilators, translators, and motors, which are all types of versors. Versors provide an algebra of spatial transformations that are different than linear algebra transformations. Entities representing the intersections of geometric surfaces can also be created by wedge products. All entities can be intersected with spheres, planes, lines, and circles. DCGA provides a higher-level algebra for working with 3D geometry in an object/entity-oriented system of mathematics above the level of the underlying implicit surface equations of algebraic geometry. DCGA could be used in the study of geometry in 3D, and also for some applications.

**Category:** Geometry

[61] **viXra:1508.0086 [pdf]**
*replaced on 2015-08-21 22:21:34*

**Authors:** Robert B. Easter

**Comments:** 43 Pages.

This paper introduces the Double Conformal Geometric Algebra (DCGA), based in the G8,2 Clifford geometric algebra. DCGA is an extension of CGA and adds geometrical entities for all 3D quadric surfaces and a toroid entity. All entities, representing various geometric surfaces and points, can be transformed in 3D space by rotors, dilators, translators, and motors, which are all types of versors. Versors provide an algebra of spatial transformations that are different than linear algebra transformations. Entities representing the intersections of geometric surfaces can also be created by wedge products. DCGA provides a higher-level algebra for working with 3D geometry in an object/entity-oriented system of mathematics above the level of the underlying implicit surface equations of algebraic geometry. DCGA could be used in the study of geometry in 3D, and also for some applications.

**Category:** Geometry

[60] **viXra:1508.0086 [pdf]**
*replaced on 2015-08-17 10:53:51*

**Authors:** Robert B. Easter

**Comments:** 43 Pages.

This paper introduces the Double Conformal Geometric Algebra (DCGA), based in the G8,2 Clifford geometric algebra. DCGA is an extension of CGA and adds geometrical entities for all 3D quadric surfaces and a toroid entity. All entities, representing various geometric surfaces and points, can be transformed in 3D space by rotors, dilators, translators, and motors, which are all types of versors. Versors provide an algebra of spatial transformations that are different than linear algebra transformations. Entities representing the intersections of geometric surfaces can also be created by wedge products. DCGA provides a higher-level algebra for working with 3D geometry in an object/entity-oriented system of mathematics above the level of the underlying homogeneous polynomial equations of algebraic geometry. DCGA could be used in the study of geometry in 3D, and also for some applications.

**Category:** Geometry

[59] **viXra:1508.0086 [pdf]**
*replaced on 2015-08-13 13:34:52*

**Authors:** Robert B. Easter

**Comments:** 43 Pages.

This paper introduces the Double Conformal Geometric Algebra (DCGA), based in the G8,2 Clifford geometric algebra. DCGA is an extension of CGA and adds geometrical entities for all 3D quadric surfaces and a toroid entity. All entities, representing various geometric surfaces and points, can be transformed in 3D space by rotors, dilators, translators, and motors, which are all types of versors. Versors provide an algebra of spatial transformations that are different than linear algebra transformations. Entities representing the intersections of geometric surfaces can also be created by wedge products. DCGA provides a higher-level algebra for working with 3D geometry in an object/entity-oriented system of mathematics above the level of the underlying homogeneous polynomial equations of algebraic geometry. DCGA could be used in the study of geometry in 3D, and also for some applications.

**Category:** Geometry

[58] **viXra:1507.0218 [pdf]**
*replaced on 2015-07-30 03:34:38*

**Authors:** Dao Thanh Oai

**Comments:** 3 Pages.

In this note, I introduce three conjectures of generalization of the Lester circle theorem, the Parry circle theorem, the Zeeman-Gossard perspector theorem respectively

**Category:** Geometry

[57] **viXra:1507.0216 [pdf]**
*replaced on 2015-07-30 03:26:55*

**Authors:** Dao Thanh Oai

**Comments:** 1 Page.

In Euclidean geometry, Feuerbach-Luchterhand theorem is a generalization of Pythagorean theorem, Stewart theorem and the British Flag theorem.....In this note, I propose two conjectures of generalization of Feuerbach-Luchterhand theorem.

**Category:** Geometry

[56] **viXra:1411.0038 [pdf]**
*replaced on 2014-11-13 02:07:02*

**Authors:** Philip Gibbs

**Comments:** 8 Pages.

There is a class of geometric problem that seeks to find the shape of largest area that can pass down a corridor of given form or turn round inside a given shape. A popular example is the moving sofa problem for a shape that can be moved round an L-shaped corner in a corridor of width one. This problem has a conjectured solution proposed by Gerver in 1992. We investigate some of these problems numerically giving strong empirical evidence that Gerver was right and that a similar solution can be constructed for the related Conway car problem.

**Category:** Geometry

[55] **viXra:1410.0160 [pdf]**
*replaced on 2015-02-18 05:44:42*

**Authors:** Wenceslao Segura González

**Comments:** 46 Pages. Spanish

The affine connection is the primary geometric element from which derive all other quantities that characterize a given geometry. In this article the concept of affine connection, its properties and the quantities derived from it are studied, we also present some of the connections that have been used in physical theories. We introduce the metric tensor and we study its relation with the affine connection. This study is intended for application in alternative theories of gravity to the General Theory of Relativity and to the unified field theories.

**Category:** Geometry

[54] **viXra:1410.0160 [pdf]**
*replaced on 2015-01-06 05:06:56*

**Authors:** Wenceslao Segura González

**Comments:** 43 Pages. Spanish

The affine connection is the primary geometric element from which derive all other quantities that characterize a given geometry. In this article the concept of affine connection, its properties and the quantities derived from it are studied, we also present some of the connections that have been used in physical theories. We introduce the metric tensor and we study its relation with the affine connection. This study is intended for application in alternative theories of gravity to the General Theory of Relativity and to the unified field theories.

**Category:** Geometry

[53] **viXra:1410.0160 [pdf]**
*replaced on 2014-12-05 12:45:26*

**Authors:** Wenceslao Segura González

**Comments:** 41 Pages. Spanish

**Category:** Geometry

[52] **viXra:1410.0160 [pdf]**
*replaced on 2014-11-11 12:24:10*

**Authors:** Wenceslao Segura González

**Comments:** 36 Pages. Spanish

**Category:** Geometry

[51] **viXra:1410.0160 [pdf]**
*replaced on 2014-10-27 11:11:39*

**Authors:** Wenceslao Segura González

**Comments:** 36 Pages. Spanish

**Category:** Geometry

[50] **viXra:1408.0191 [pdf]**
*replaced on 2014-08-31 13:31:01*

**Authors:** Tobías de Jesús Rosas Soto

**Comments:** 17 Pages. Artículo en español, con resumen en inglés. Contiene ecuaciones, y 13 figuras, a color para mejor comprensión.

Usando la noción de C-ortocentro se extienden, a planos de Minkowski en general, nociones de la geometría clásica relacionadas con un triángulo, como por ejemplo: puntos de Euler, triángulo de Euler, puntos de Poncelet. Se muestran propiedades de estas nociones y sus relaciones con la circunferencia de Feuerbach. Se estudian sistemas C-ortocéntricos formados por puntos presentes en dichas nociones y se establecen relaciones con la ortogonalidad isósceles y cordal. Además, se
prueba que la imagen homotética de un sistema C-ortocéntrico es un sistema C-ortocéntrico.
---
Using the notion of C-orthocenter, notions of the classic euclidean geometry related with a triangle, as for example: Euler points; Euler’s triangle; and Poncelet’s points, are extended to Minkowski planes in general. Properties of these notions and their relations with the Feuerbach’s circle, are shown. C-orthocentric systems formed by points in the above notions are studied and relations with the isosceles and chordal orthogonality, are established. In addition, there is proved that the homothetic image of a C-orthocentric system is a C-orthocentric system.

**Category:** Geometry