[5] **viXra:1012.0052 [pdf]**
*replaced on 17 Jan 2011*

**Authors:** Giuliano Bettini

**Comments:** 9 pages, v3 in Italian, v2 in English, corrections to the tables, and a new table added.

There are 32 possible combinations of symmetry operations that define the external symmetry of
crystals. These 32 possible combinations result in the 32 crystal classes.
But for a radar engineer it is inevitable to associate "32" to "5 bits".
I submit a tentative classification of the 32 crystal classes with a 5 bit classification, obviously with
a (tentative) physical meaning of each bit.
Each bit means a physical property.

**Category:** Mathematical Physics

[4] **viXra:1012.0031 [pdf]**
*replaced on 16 Dec 2010*

**Authors:** Elemér E Rosinger

**Comments:** 9 pages

A class of non-Cartesian physical systems, [7], are those whose
composite state spaces are given by significantly extended tensor products.
A more detailed presentation of the way such extended tensor products
are constructed is offered, based on a step by step comparison with the
construction of usual tensor products. This presentation clarifies the
extent to which the extended tensor products are indeed more general
than the usual ones.

**Category:** Mathematical Physics

[3] **viXra:1012.0020 [pdf]**
*submitted on 8 Dec 2010*

**Authors:** Elemer E Rosinger

**Comments:** 6 pages

The following open problem is presented and motivated : Are there
physical systems whose state spaces do not compose according to either
the Cartesian product, as classical systems do, or the usual tensor
product, as quantum systems do ?

**Category:** Mathematical Physics

[2] **viXra:1012.0014 [pdf]**
*submitted on 4 Dec 2010*

**Authors:** Elemer E Rosinger

**Comments:** 28 pages

Much of Mathematics, and therefore Physics as well, have been
limited by four rather consequential restrictions. Two of them are ancient
taboos, one is an ancient and no longer felt as such bondage, and the
fourth is a surprising omission in Algebra. The paper brings to the
attention of those interested these four restrictions, as well as the fact
that each of them has by now ways, even if hardly yet known ones, to
overcome them.

**Category:** Mathematical Physics

[1] **viXra:1012.0002 [pdf]**
*submitted on 1 Dec 2010*

**Authors:** Arkadiusz Jadczyk

**Comments:** 7 pages, To appear in Advances in Applied Clifford Algebras

We study in some detail the structure of the projective quadric Q'
obtained by taking the quotient of the isotropic cone in a standard pseudohermitian
space H_{p,q} with respect to the positive real numbers R^{+} and,
further, by taking the quotient ~Q = Q'/U(1). The case of signature (1. 1)
serves as an illustration. ~Q is studied as a compactification of RxH_{p-1,q-1}

**Category:** Mathematical Physics