Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Contractive spectral triples for crossed products   Connes showed that spectral triples encode (noncommutative) metric
information. Further, Connes and Moscovici in their metric bundle construction
showed that, as with the Takesaki duality theorem, forming a crossed product
spectral triple can substantially simplify the structure. In a recent paper,
Bellissard, Marcolli and Reihani (among other things) studied in depth metric
notions for spectral triples and crossed product spectral triples for
$Z$-actions, with applications in number theory and coding theory. In the work
of Connes and Moscovici, crossed products involving groups of diffeomorphisms
and even of \'{e}tale groupoids are required. With this motivation, the present
paper develops part of the Bellissard-Marcolli-Reihani theory for a general
discrete group action, and in particular, introduces coaction spectral triples
and their associated metric notions. The isometric condition is replaced by the
contractive condition.

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The categories of this paper are: dg-ga
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The categories of this paper are: hep-ex
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The categories of this paper are: funct-an
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The categories of this paper are: math-ph
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The categories of this paper are: plasm-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: quant-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: nlin
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The categories of this paper are: eess
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The categories of this paper are: gr-qc
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The categories of this paper are: econ
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The categories of this paper are: q-fin
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The categories of this paper are: adap-org
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The categories of this paper are: chao-dyn
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The categories of this paper are: hep-th