Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Model Theory of Fields with Virtually Free Group Actions   For a group $G$, we define the notion of a $G$-kernel and show that the
properties of $G$-kernels are closely related with the existence of a model
companion of the theory of Galois actions of $G$. Using Bass-Serre theory, we
show that this model companion exists for virtually free groups generalizing
the existing results about free groups and finite groups. We show that the new
theories we obtain are not simple and not even NTP$_2$.

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The categories of this paper are: chem-ph
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The categories of this paper are: atom-ph
16
The categories of this paper are: stat
33
The categories of this paper are: plasm-ph
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The categories of this paper are: cmp-lg
4
The categories of this paper are: cond-mat
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The categories of this paper are: solv-int
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The categories of this paper are: nucl-th
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The categories of this paper are: gr-qc
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The categories of this paper are: bayes-an
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The categories of this paper are: q-fin
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The categories of this paper are: nucl-ex
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The categories of this paper are: quant-ph
1
The categories of this paper are: cs
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The categories of this paper are: q-alg
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The categories of this paper are: eess