Orbital integrals and K-theory classes

dc.contributor.authorHochs, P.
dc.contributor.authorWang, H.
dc.date.issued2019
dc.description.abstractLet G be a semisimple Lie group with discrete series. We use maps K₀(C∗rG)→C defined by orbital integrals to recover group theoretic information about G, including information contained in K-theory classes not associated to the discrete series. An important tool is a fixed point formula for equivariant indices obtained by the authors in an earlier paper. Applications include a tool to distinguish classes in K₀(C∗rG), the (known) injectivity of Dirac induction, versions of Selberg’s principle in K-theory and for matrix coefficients of the discrete series, a Tannaka-type duality, and a way to extract characters of representations from K-theory. Finally, we obtain a continuity property near the identity element of G of families of maps K₀(C∗rG)→C, parametrised by semisimple elements of G, defined by stable orbital integrals. This implies a continuity property for L-packets of discrete series characters, which in turn can be used to deduce a (well-known) expression for formal degrees of discrete series representations from Harish-Chandra’s character formula.
dc.description.statementofresponsibilityPeter Hochs and Hang Wang
dc.identifier.citationAnnals of K-Theory, 2019; 4(2):185-209
dc.identifier.doi10.2140/akt.2019.4.185
dc.identifier.issn2379-1683
dc.identifier.issn2379-1691
dc.identifier.orcidHochs, P. [0000-0001-9232-2936]
dc.identifier.urihttp://hdl.handle.net/2440/128691
dc.language.isoen
dc.publisherMathematical Sciences Publishers
dc.relation.granthttp://purl.org/au-research/grants/arc/DE160100525
dc.rights© 2019 Mathematical Sciences Publishers
dc.source.urihttps://doi.org/10.2140/akt.2019.4.185
dc.subjectK-theory of group C*-algebras; orbital integral; equivariant index; semisimple Lie group; Connes–Kasparov conjecture
dc.titleOrbital integrals and K-theory classes
dc.typeJournal article
pubs.publication-statusPublished

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