Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the long-time behaviour of age and trait structured population
  dynamics   We study the long-time behaviour of a population structured by age and a
phenotypic trait under a selection-mutation dynamics. By analysing spectral
properties of a family of positive operators on measure spaces, we show the
existence of eventually singular stationary solutions. When the stationary
measures are absolutely continuous with a continuous density, we show the
convergence of the dynamics to the unique equilibrium.

13
The categories of this paper are: quant-ph
22
The categories of this paper are: chao-dyn
17
The categories of this paper are: q-fin
4
The categories of this paper are: cond-mat
28
The categories of this paper are: alg-geom
37
The categories of this paper are: supr-con
8
The categories of this paper are: hep-ex
34
The categories of this paper are: chem-ph
18
The categories of this paper are: econ
9
The categories of this paper are: nlin
14
The categories of this paper are: math-ph
15
The categories of this paper are: nucl-ex
11
The categories of this paper are: hep-lat
3
The categories of this paper are: physics
29
The categories of this paper are: funct-an
16
The categories of this paper are: stat