Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On a nonlocal aggregation model with nonlinear diffusion   We consider a nonlocal aggregation equation with nonlinear diffusion which
arises from the study of biological aggregation dynamics. As a degenerate
parabolic problem, we prove the well-posedness, continuation criteria and
smoothness of local solutions. For compactly supported nonnegative smooth
initial data we prove that the gradient of the solution develops
$L_x^\infty$-norm blowup in finite time.

23
The categories of this paper are: solv-int
33
The categories of this paper are: plasm-ph
9
The categories of this paper are: nlin
18
The categories of this paper are: econ
0
The categories of this paper are: hep-ph
26
The categories of this paper are: bayes-an
37
The categories of this paper are: supr-con
10
The categories of this paper are: q-bio
8
The categories of this paper are: hep-ex
35
The categories of this paper are: mtrl-th
36
The categories of this paper are: cmp-lg
34
The categories of this paper are: chem-ph
27
The categories of this paper are: comp-gas
11
The categories of this paper are: hep-lat
28
The categories of this paper are: alg-geom
4
The categories of this paper are: cond-mat