Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A proof of Perko's conjectures for the Bogdanov-Takens system   The Bogdanov-Takens system has at most one limit cycle and, in the parameter
space, it exists between a Hopf and a saddle-loop bifurcation curves. The aim
of this paper is to prove the Perko's conjectures about some analytic
properties of the saddle-loop bifurcation curve. Moreover, we provide sharp
piecewise algebraic upper and lower bounds for this curve.

19
The categories of this paper are: eess
4
The categories of this paper are: cond-mat
13
The categories of this paper are: quant-ph
20
The categories of this paper are: acc-phys
26
The categories of this paper are: bayes-an
9
The categories of this paper are: nlin
29
The categories of this paper are: funct-an
32
The categories of this paper are: atom-ph
14
The categories of this paper are: math-ph
34
The categories of this paper are: chem-ph
0
The categories of this paper are: hep-ph
18
The categories of this paper are: econ
27
The categories of this paper are: comp-gas
35
The categories of this paper are: mtrl-th
6
The categories of this paper are: astro-ph
28
The categories of this paper are: alg-geom