Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the Combinatorics of Palindromes and Antipalindromes   We prove a number of results on the structure and enumeration of palindromes
and antipalindromes. In particular, we study conjugates of palindromes,
palindromic pairs, rich words, and the counterparts of these notions for
antipalindromes.

7
The categories of this paper are: hep-th
37
The categories of this paper are: supr-con
33
The categories of this paper are: plasm-ph
3
The categories of this paper are: physics
12
The categories of this paper are: nucl-th
20
The categories of this paper are: acc-phys
28
The categories of this paper are: alg-geom
16
The categories of this paper are: stat
26
The categories of this paper are: bayes-an
22
The categories of this paper are: chao-dyn
4
The categories of this paper are: cond-mat
30
The categories of this paper are: q-alg
11
The categories of this paper are: hep-lat
0
The categories of this paper are: hep-ph
17
The categories of this paper are: q-fin
10
The categories of this paper are: q-bio