Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The essential ideal in group cohomology does not square to zero   Let G be the Sylow 2-subgroup of the unitary group $SU_3(4)$. We find two
essential classes in the mod-2 cohomology ring of G whose product is nonzero.
In fact, the product is the ``last survivor'' of Benson-Carlson duality. Recent
work of Pakianathan and Yalcin then implies a result about connected graphs
with an action of G. Also, there exist essential classes which cannot be
written as sums of transfers from proper subgroups.
  This phenomenon was first observed on the computer. The argument given here
uses the elegant calculation by J. Clark, with minor corrections.

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The categories of this paper are: bayes-an
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The categories of this paper are: eess
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The categories of this paper are: patt-sol
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The categories of this paper are: hep-th
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The categories of this paper are: alg-geom
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The categories of this paper are: astro-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: chem-ph
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The categories of this paper are: cond-mat
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The categories of this paper are: hep-ex
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The categories of this paper are: atom-ph
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The categories of this paper are: physics
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The categories of this paper are: hep-lat
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The categories of this paper are: mtrl-th
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The categories of this paper are: math-ph
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The categories of this paper are: nucl-th