Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Periodic solutions for a non-monotone family of delayed differential
  equations with applications to Nicholson systems   For a family of $n$-dimensional periodic delay differential equations which
encompasses a broad set of models used in structured population dynamics, the
existence of a positive periodic solution is obtained under very mild
conditions. The proof uses the Schauder fixed point theorem and relies on the
permanence of the system. A general criterion for the existence of a positive
periodic solution for Nicholson's blowflies periodic systems (with both
distributed and discrete time-varying delays) is derived as a simple
application of our main result, generalizing the few existing results
concerning multi-dimensional Nicholson models.
  In the case of a Nicholson system with discrete delays all multiples of the
period, the global attractivity of the positive periodic solution is further
analyzed, improving results in recent literature.

21
The categories of this paper are: adap-org
15
The categories of this paper are: nucl-ex
23
The categories of this paper are: solv-int
34
The categories of this paper are: chem-ph
1
The categories of this paper are: cs
36
The categories of this paper are: cmp-lg
26
The categories of this paper are: bayes-an
20
The categories of this paper are: acc-phys
14
The categories of this paper are: math-ph
35
The categories of this paper are: mtrl-th
9
The categories of this paper are: nlin
32
The categories of this paper are: atom-ph
10
The categories of this paper are: q-bio
18
The categories of this paper are: econ
0
The categories of this paper are: hep-ph
13
The categories of this paper are: quant-ph