Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On a composition of digraphs   Many "good" topologies for interconnection networks are based on line
digraphs of regular digraphs. These digraphs support unitary matrices. We
propose the property "being the digraph of a unitary matrix" as additional
criterion for the design of new interconnection networks. We define a
composition of digraphs, which we call diagonal union. Diagonal union can be
used to construct digraphs of unitary matrices. We remark that digraphs
obtained via diagonal union are state split graphs, as defined in symbolic
dynamics. Finally, we list some potential directions for future research.

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The categories of this paper are: solv-int
32
The categories of this paper are: atom-ph
15
The categories of this paper are: nucl-ex
22
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: dg-ga
12
The categories of this paper are: nucl-th
25
The categories of this paper are: patt-sol
6
The categories of this paper are: astro-ph
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The categories of this paper are: acc-phys
14
The categories of this paper are: math-ph
13
The categories of this paper are: quant-ph
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The categories of this paper are: chem-ph
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The categories of this paper are: econ
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The categories of this paper are: supr-con
26
The categories of this paper are: bayes-an