Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: New Self-Dual Codes from 2x2 Block Circulant Matrices, Group Rings and
  Neighbours of Neighbours   In this paper, we construct self-dual codes from a construction that involves
2x2 block circulant matrices, group rings and a reverse circulant matrix. We
provide conditions whereby this construction can yield self-dual codes. We
construct self-dual codes of various lengths over F2, F2 + uF2 and F4 + uF4.
Using extensions, neighbours and neighbours of neighbours, we construct 32 new
self-dual codes of length 68.

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The categories of this paper are: cond-mat
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The categories of this paper are: stat
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The categories of this paper are: adap-org
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The categories of this paper are: hep-lat
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The categories of this paper are: alg-geom
32
The categories of this paper are: atom-ph
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The categories of this paper are: q-fin
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The categories of this paper are: hep-ex
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The categories of this paper are: physics
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The categories of this paper are: cmp-lg
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The categories of this paper are: chao-dyn
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The categories of this paper are: dg-ga
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The categories of this paper are: quant-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: q-bio
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The categories of this paper are: hep-th