Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Periodic behaviors   This paper studies behaviors that are defined on a torus, or equivalently,
behaviors defined in spaces of periodic functions, and establishes their basic
properties analogous to classical results of Malgrange, Palamodov, Oberst et
al. for behaviors on R^n. These properties - in particular the Nullstellensatz
describing the Willems closure - are closely related to integral and rational
points on affine algebraic varieties.

25
The categories of this paper are: patt-sol
24
The categories of this paper are: dg-ga
26
The categories of this paper are: bayes-an
4
The categories of this paper are: cond-mat
35
The categories of this paper are: mtrl-th
29
The categories of this paper are: funct-an
10
The categories of this paper are: q-bio
34
The categories of this paper are: chem-ph
15
The categories of this paper are: nucl-ex
5
The categories of this paper are: gr-qc
20
The categories of this paper are: acc-phys
11
The categories of this paper are: hep-lat
31
The categories of this paper are: ao-sci
17
The categories of this paper are: q-fin
14
The categories of this paper are: math-ph
6
The categories of this paper are: astro-ph