Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: When are permutation invariants Cohen-Macaulay over all fields?   We prove that the polynomial invariants of a permutation group are
Cohen-Macaulay for any choice of coefficient field if and only if the group is
generated by transpositions, double transpositions, and 3-cycles. This unites
and generalizes several previously known results. The "if" direction of the
argument uses Stanley-Reisner theory and a recent result of Christian Lange in
orbifold theory. The "only-if" direction uses a local-global result based on a
theorem of Raynaud to reduce the problem to an analysis of inertia groups, and
a combinatorial argument to identify inertia groups that obstruct
Cohen-Macaulayness.

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The categories of this paper are: dg-ga
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The categories of this paper are: nlin
5
The categories of this paper are: gr-qc
35
The categories of this paper are: mtrl-th
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The categories of this paper are: bayes-an
0
The categories of this paper are: hep-ph
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The categories of this paper are: q-bio
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The categories of this paper are: supr-con
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The categories of this paper are: adap-org
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The categories of this paper are: eess
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The categories of this paper are: acc-phys
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The categories of this paper are: quant-ph
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The categories of this paper are: stat
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The categories of this paper are: solv-int
1
The categories of this paper are: cs
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The categories of this paper are: comp-gas