Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Axiomatizing rectangular grids with no extra non-unary relations   We construct a formula $\phi$ which axiomatizes non-narrow rectangular grids
without using any binary relations other than the grid neighborship relations.
As a corollary, we prove that a set $A \subseteq \mathbb{N}$ is a spectrum of a
formula which has only planar models if numbers $n \in A$ can be recognized by
a non-deterministic Turing machine (or a one-dimensional cellular automaton) in
time $t(n)$ and space $s(n)$, where $t(n)s(n) \leq n$ and $t(n),s(n) =
\Omega(\log(n))$.

27
The categories of this paper are: comp-gas
0
The categories of this paper are: hep-ph
13
The categories of this paper are: quant-ph
17
The categories of this paper are: q-fin
20
The categories of this paper are: acc-phys
35
The categories of this paper are: mtrl-th
12
The categories of this paper are: nucl-th
36
The categories of this paper are: cmp-lg
21
The categories of this paper are: adap-org
10
The categories of this paper are: q-bio
6
The categories of this paper are: astro-ph
2
The categories of this paper are: math
29
The categories of this paper are: funct-an
19
The categories of this paper are: eess
30
The categories of this paper are: q-alg
16
The categories of this paper are: stat