Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Srb measures for C $\infty$ surface diffeomorphisms   A C $\infty$ surface diffeomorphism admits a SRB measure if and only if the
set {x, lim sup n 1 n log dxf n > 0} has positive Lebesgue measure. Moreover
the basins of the ergodic SRB measures are covering this set Lebesgue almost
everywhere.

24
The categories of this paper are: dg-ga
29
The categories of this paper are: funct-an
6
The categories of this paper are: astro-ph
14
The categories of this paper are: math-ph
32
The categories of this paper are: atom-ph
12
The categories of this paper are: nucl-th
8
The categories of this paper are: hep-ex
19
The categories of this paper are: eess
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
5
The categories of this paper are: gr-qc
7
The categories of this paper are: hep-th
36
The categories of this paper are: cmp-lg
9
The categories of this paper are: nlin
37
The categories of this paper are: supr-con