Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Subdifferential of the joint numerical radius   An expression for the subdifferential of the joint numerical radius is
obtained. Its applications to the best approximation problems in the joint
numerical radius are discussed.

15
The categories of this paper are: nucl-ex
17
The categories of this paper are: q-fin
12
The categories of this paper are: nucl-th
22
The categories of this paper are: chao-dyn
6
The categories of this paper are: astro-ph
35
The categories of this paper are: mtrl-th
29
The categories of this paper are: funct-an
19
The categories of this paper are: eess
7
The categories of this paper are: hep-th
5
The categories of this paper are: gr-qc
26
The categories of this paper are: bayes-an
30
The categories of this paper are: q-alg
0
The categories of this paper are: hep-ph
21
The categories of this paper are: adap-org
4
The categories of this paper are: cond-mat
1
The categories of this paper are: cs