Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: No extremal square-free words over large alphabets   A word is square-free if it does not contain any square (a word of the form
$XX$), and is extremal square-free if it cannot be extended to a new
square-free word by inserting a single letter at any position. Grytczuk,
Kordulewski, and Niewiadomski proved that there exist infinitely many ternary
extremal square-free words. We establish that there are no extremal square-free
words over any alphabet of size at least 17.

28
The categories of this paper are: alg-geom
31
The categories of this paper are: ao-sci
9
The categories of this paper are: nlin
3
The categories of this paper are: physics
15
The categories of this paper are: nucl-ex
14
The categories of this paper are: math-ph
0
The categories of this paper are: hep-ph
27
The categories of this paper are: comp-gas
18
The categories of this paper are: econ
24
The categories of this paper are: dg-ga
33
The categories of this paper are: plasm-ph
22
The categories of this paper are: chao-dyn
37
The categories of this paper are: supr-con
13
The categories of this paper are: quant-ph
32
The categories of this paper are: atom-ph
10
The categories of this paper are: q-bio