Letters in Mathematical Physics

, Volume 75, Issue 3, pp 235–254 | Cite as

Local Index Formula on the Equatorial Podleś Sphere

  • Francesco D’andrea
  • Ludwik Da̧browski


We discuss spectral properties of the equatorial Podleś sphere S q 2 . As a preparation we also study the ‘degenerate’ (i.e. q=0) case (related to the quantum disk). Over S q 2 we consider two different spectral triples:one related to the Fock representation of the Toeplitz algebra and the isopectral one given in [7]. After the identification of the smooth pre-C *-algebra we compute the dimension spectrum and residues. We check the nontriviality of the (noncommutative) Chern character of the associated Fredholm modules by computing the pairing with the fundamental projector of the C *-algebra (the nontrivial generator of the K 0-group) as well as the pairing with the q-analogue of the Bott projector. Finally, we show that the local index formula is trivially satisfied.

Mathematics Subject Classifications (2000).

Primary 58B34 Secondary 17B37 


Noncommutative geometry spectral triple quantum sphere 


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Copyright information

© Springer 2006

Authors and Affiliations

  1. 1.Scuola Internazionale Superiore di Studi AvanzatiTriesteItaly

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