Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Central idempotents of the bifree and left-free double Burnside ring   We determine the blocks, i.e., the primitive central idempotents, of the
bifree double Burnside ring $B^\Delta(G,G)$ and the left-free double Burnside
ring $B^{\trl}(G,G)$, as well as the primitive central idempotents of the
algebras arising from scalar extension to $\QQ$.

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The categories of this paper are: plasm-ph
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The categories of this paper are: hep-ph
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The categories of this paper are: supr-con
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The categories of this paper are: q-alg
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The categories of this paper are: quant-ph
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The categories of this paper are: chao-dyn
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The categories of this paper are: alg-geom
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The categories of this paper are: cmp-lg
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The categories of this paper are: gr-qc
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The categories of this paper are: q-fin
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The categories of this paper are: dg-ga
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The categories of this paper are: cond-mat
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The categories of this paper are: acc-phys
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The categories of this paper are: adap-org
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The categories of this paper are: nucl-ex
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The categories of this paper are: hep-th