Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: 2- and 3-Covariant Equiangular Tight Frames   Equiangular tight frames (ETFs) are configurations of vectors which are
optimally geometrically spread apart and provide resolutions of the identity.
Many known constructions of ETFs are group covariant, meaning they result from
the action of a group on a vector, like all known constructions of symmetric,
informationally complete, positive operator-valued measures. In this short
article, some results characterizing the transitivity of the symmetry groups of
ETFs will be presented as well as a proof that an infinite class of so-called
Gabor-Steiner ETFs are roux lines, where roux lines are a generalization of
doubly transitive lines.

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The categories of this paper are: gr-qc
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The categories of this paper are: hep-ex
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The categories of this paper are: chao-dyn
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The categories of this paper are: mtrl-th
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The categories of this paper are: nucl-ex
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The categories of this paper are: supr-con
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The categories of this paper are: quant-ph
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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: hep-lat
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The categories of this paper are: math-ph
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The categories of this paper are: adap-org
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The categories of this paper are: q-alg
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The categories of this paper are: alg-geom
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The categories of this paper are: bayes-an
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The categories of this paper are: ao-sci