Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Initial-boundary value problems for fractional diffusion equations with
  time-dependent coeffcients   We discuss an initial-boundary value problem for a fractional diffusion
equation with Caputo time-fractional derivative where the coefficients are
dependent on spatial and time variables and the zero Dirichlet boundary
condition is attached. We prove the unique existence of weak and regular
solutions.

30
The categories of this paper are: q-alg
18
The categories of this paper are: econ
7
The categories of this paper are: hep-th
20
The categories of this paper are: acc-phys
11
The categories of this paper are: hep-lat
34
The categories of this paper are: chem-ph
24
The categories of this paper are: dg-ga
3
The categories of this paper are: physics
22
The categories of this paper are: chao-dyn
37
The categories of this paper are: supr-con
26
The categories of this paper are: bayes-an
12
The categories of this paper are: nucl-th
6
The categories of this paper are: astro-ph
25
The categories of this paper are: patt-sol
32
The categories of this paper are: atom-ph
19
The categories of this paper are: eess