Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The entropy of ``strange'' billiards inside n-simplexes   In the present work we investigate a new type of billiards defined inside of
$n$--simplex regions. We determine an invariant ergodic (SRB) measure of the
dynamics for any dimension. In using symbolic dynamics, the (KS or metric)
entropy is computed and we find that the system is chaotic for all cases $n>2$.

13
The categories of this paper are: quant-ph
37
The categories of this paper are: supr-con
32
The categories of this paper are: atom-ph
25
The categories of this paper are: patt-sol
36
The categories of this paper are: cmp-lg
3
The categories of this paper are: physics
14
The categories of this paper are: math-ph
20
The categories of this paper are: acc-phys
29
The categories of this paper are: funct-an
35
The categories of this paper are: mtrl-th
33
The categories of this paper are: plasm-ph
18
The categories of this paper are: econ
24
The categories of this paper are: dg-ga
27
The categories of this paper are: comp-gas
5
The categories of this paper are: gr-qc
6
The categories of this paper are: astro-ph