Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Green fields   We introduce {\em Green fields}, as commutative Green biset functors with no
non-trivial ideals. We state some of their properties and give examples of
known Green biset functors which are Green fields. Among the properties, we
prove some criterions ensuring that a Green field is semisimple. Finally, we
describe a type of Green field for which its category of modules is equivalent
to a category of vector spaces over a field.

20
The categories of this paper are: acc-phys
29
The categories of this paper are: funct-an
9
The categories of this paper are: nlin
28
The categories of this paper are: alg-geom
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The categories of this paper are: solv-int
0
The categories of this paper are: hep-ph
15
The categories of this paper are: nucl-ex
30
The categories of this paper are: q-alg
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The categories of this paper are: math-ph
22
The categories of this paper are: chao-dyn
3
The categories of this paper are: physics
7
The categories of this paper are: hep-th
31
The categories of this paper are: ao-sci
1
The categories of this paper are: cs
8
The categories of this paper are: hep-ex
37
The categories of this paper are: supr-con