Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Maximum principle for time-fractional parabolic equations with a
  reaction coefficient of arbitrary sign   We consider time-fractional parabolic equations with a Caputo time derivative
of order $\alpha\in(0,1)$. For such equations, we give an elementary proof of
the weak maximum principle under no assumptions on the sign of the reaction
coefficient. This proof is also extended for weak solutions, as well as for
various types of boundary conditions and variable-coefficient variable-order
multiterm time-fractional parabolic equations.

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The categories of this paper are: math-ph
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The categories of this paper are: econ
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The categories of this paper are: solv-int
29
The categories of this paper are: funct-an
9
The categories of this paper are: nlin
34
The categories of this paper are: chem-ph
7
The categories of this paper are: hep-th
8
The categories of this paper are: hep-ex
35
The categories of this paper are: mtrl-th
30
The categories of this paper are: q-alg
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The categories of this paper are: supr-con
31
The categories of this paper are: ao-sci
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The categories of this paper are: nucl-th
4
The categories of this paper are: cond-mat
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The categories of this paper are: eess
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The categories of this paper are: nucl-ex