Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Torsion homology and cellular approximation   In this note we describe the role of the Schur multiplier in the structure of
the $p$-torsion of discrete groups. More concretely, we show how the knowledge
of $H_2G$ allows to approximate many groups by colimits of copies of finite
$p$-groups. Our examples include interesting families of non-commutative
infinite groups, including Burnside groups, certain solvable examples and the
first Grigorchuk group. We also provide a counterexample for a conjecture of E.
Farjoun.

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The categories of this paper are: gr-qc
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The categories of this paper are: chem-ph
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The categories of this paper are: solv-int
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The categories of this paper are: bayes-an
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The categories of this paper are: nucl-th
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The categories of this paper are: physics
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The categories of this paper are: ao-sci
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The categories of this paper are: dg-ga
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The categories of this paper are: q-fin
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The categories of this paper are: funct-an
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The categories of this paper are: econ
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The categories of this paper are: plasm-ph
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The categories of this paper are: q-alg
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The categories of this paper are: nucl-ex
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The categories of this paper are: hep-ex
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The categories of this paper are: atom-ph