Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: An extension theorem for some pseudo-differential operators
35
The categories of this paper are: mtrl-th
14
The categories of this paper are: math-ph
15
The categories of this paper are: nucl-ex
29
The categories of this paper are: funct-an
1
The categories of this paper are: cs
17
The categories of this paper are: q-fin
3
The categories of this paper are: physics
23
The categories of this paper are: solv-int
10
The categories of this paper are: q-bio
18
The categories of this paper are: econ
25
The categories of this paper are: patt-sol
9
The categories of this paper are: nlin
33
The categories of this paper are: plasm-ph
22
The categories of this paper are: chao-dyn
20
The categories of this paper are: acc-phys
16
The categories of this paper are: stat