Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Isomorphism classes of four dimensional nilpotent associative algebras
  over a field   In this paper we classify the isomorphism classes of four dimensional
nilpotent associative algebras over a field F, studying regular subgroups of
the affine group AGL_4(F). In particular we provide explicit representatives
for such classes when F is a finite field, the real field R or an algebraically
closed field.

24
The categories of this paper are: dg-ga
10
The categories of this paper are: q-bio
15
The categories of this paper are: nucl-ex
4
The categories of this paper are: cond-mat
6
The categories of this paper are: astro-ph
21
The categories of this paper are: adap-org
17
The categories of this paper are: q-fin
11
The categories of this paper are: hep-lat
28
The categories of this paper are: alg-geom
33
The categories of this paper are: plasm-ph
37
The categories of this paper are: supr-con
22
The categories of this paper are: chao-dyn
32
The categories of this paper are: atom-ph
26
The categories of this paper are: bayes-an
7
The categories of this paper are: hep-th
12
The categories of this paper are: nucl-th