Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Four-point boundary value problems for a coupled system of fractional
  differential equations with $\psi$-Caputo fractional derivatives   In this paper, we focus on the existence and uniqueness of solutions of
boundary value problems for a coupled system of fractional differential
equations with four-point boundary conditions involving $\psi$-Caputo
fractional derivatives. Our investigation is based on Leray-Schauder
alternative and Banach's fixed point theorem. Two examples are presented to
illustrate the applicability of the results developed.

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The categories of this paper are: funct-an
5
The categories of this paper are: gr-qc
25
The categories of this paper are: patt-sol
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The categories of this paper are: q-alg
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The categories of this paper are: chem-ph
21
The categories of this paper are: adap-org
9
The categories of this paper are: nlin
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The categories of this paper are: alg-geom
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The categories of this paper are: dg-ga
0
The categories of this paper are: hep-ph
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The categories of this paper are: quant-ph
3
The categories of this paper are: physics
12
The categories of this paper are: nucl-th
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The categories of this paper are: nucl-ex
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The categories of this paper are: hep-th
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The categories of this paper are: q-fin