Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On certain labelled directed graphs of symbolic dynamics   We describe classes of semisynchronizing, non-synchronizing subshifts, that
are closed under topological conjugacy. The subshifts that belong to these
classes satisfy a strong hypothesis of context-freeness and are canonically
presented by means of Shannon graphs that have the structure of a pda.

0
The categories of this paper are: hep-ph
28
The categories of this paper are: alg-geom
13
The categories of this paper are: quant-ph
23
The categories of this paper are: solv-int
11
The categories of this paper are: hep-lat
29
The categories of this paper are: funct-an
6
The categories of this paper are: astro-ph
5
The categories of this paper are: gr-qc
17
The categories of this paper are: q-fin
25
The categories of this paper are: patt-sol
9
The categories of this paper are: nlin
3
The categories of this paper are: physics
16
The categories of this paper are: stat
18
The categories of this paper are: econ
15
The categories of this paper are: nucl-ex
14
The categories of this paper are: math-ph