Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Letter graphs and geometric grid classes of permutations:
  characterization and recognition   In this paper, we reveal an intriguing relationship between two seemingly
unrelated notions: letter graphs and geometric grid classes of permutations. An
important property common for both of them is well-quasi-orderability,
implying, in a non-constructive way, a polynomial-time recognition of geometric
grid classes of permutations and $k$-letter graphs for a fixed $k$. However,
constructive algorithms are available only for $k=2$. In this paper, we present
the first constructive polynomial-time algorithm for the recognition of
$3$-letter graphs. It is based on a structural characterization of graphs in
this class.

37
The categories of this paper are: supr-con
36
The categories of this paper are: cmp-lg
16
The categories of this paper are: stat
28
The categories of this paper are: alg-geom
20
The categories of this paper are: acc-phys
27
The categories of this paper are: comp-gas
29
The categories of this paper are: funct-an
24
The categories of this paper are: dg-ga
26
The categories of this paper are: bayes-an
7
The categories of this paper are: hep-th
19
The categories of this paper are: eess
12
The categories of this paper are: nucl-th
22
The categories of this paper are: chao-dyn
15
The categories of this paper are: nucl-ex
3
The categories of this paper are: physics
25
The categories of this paper are: patt-sol