Geometry

1411 Submissions

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

The Orthogonal Planes Split of Quaternions and Its Relation to Quaternion Geometry of Rotations

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

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

The 3D Visualization of E8 Using Anh4 Folding Matrix, Math Version

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

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

A Computational Study of Sofas and Cars

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