Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Difference Methods and Ferrero Pairs   We present a construction method of BIB-designs from a finite group G and a
group of automorphisms \Phi on G such that |\Phi(x)| = |\Phi| for all x in G, x
<> 0. By using a generalization of the concept of a difference family we can so
unify several previous constructions of BIB-designs from planar near-rings.

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The categories of this paper are: hep-lat
37
The categories of this paper are: supr-con
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The categories of this paper are: nucl-th
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The categories of this paper are: stat
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The categories of this paper are: astro-ph
5
The categories of this paper are: gr-qc
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The categories of this paper are: patt-sol
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The categories of this paper are: funct-an
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The categories of this paper are: nlin
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The categories of this paper are: bayes-an
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The categories of this paper are: q-alg
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The categories of this paper are: adap-org
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The categories of this paper are: math-ph
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The categories of this paper are: chao-dyn
7
The categories of this paper are: hep-th
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The categories of this paper are: mtrl-th