Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Four limit cycles from perturbing quadratic integrable systems by
  quadratic polynomials   In this paper, we give a positive answer to the open question: Can there
exist 4 limit cycles in quadratic near-integrable polynomial systems? It is
shown that when a quadratic integrable system has two centers and is perturbed
by quadratic polynomials, it can generate at least 4 limit cycles with (3,1)
distribution. The method of Melnikov function is used.

26
The categories of this paper are: bayes-an
13
The categories of this paper are: quant-ph
7
The categories of this paper are: hep-th
16
The categories of this paper are: stat
19
The categories of this paper are: eess
1
The categories of this paper are: cs
31
The categories of this paper are: ao-sci
25
The categories of this paper are: patt-sol
34
The categories of this paper are: chem-ph
35
The categories of this paper are: mtrl-th
29
The categories of this paper are: funct-an
37
The categories of this paper are: supr-con
12
The categories of this paper are: nucl-th
11
The categories of this paper are: hep-lat
32
The categories of this paper are: atom-ph
28
The categories of this paper are: alg-geom