Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Null systems in the non-minimal case   In this paper, it is shown that if a dynamical system is null and distal,
then it is equicontinuous. It turns out that a null system with closed proximal
relation is mean equicontinuous. As a direct application, it follows that a
null dynamical system with dense minimal points is also mean equicontinuous.
Meanwhile, a distal system with trivial $\text{Ind}_{fip}$-pairs, and a
non-trivial regionally proximal relation of order $\infty$ is constructed.

23
The categories of this paper are: solv-int
27
The categories of this paper are: comp-gas
31
The categories of this paper are: ao-sci
5
The categories of this paper are: gr-qc
14
The categories of this paper are: math-ph
36
The categories of this paper are: cmp-lg
4
The categories of this paper are: cond-mat
21
The categories of this paper are: adap-org
1
The categories of this paper are: cs
0
The categories of this paper are: hep-ph
12
The categories of this paper are: nucl-th
33
The categories of this paper are: plasm-ph
29
The categories of this paper are: funct-an
11
The categories of this paper are: hep-lat
35
The categories of this paper are: mtrl-th
32
The categories of this paper are: atom-ph