Relative Cuntz-Pimsner algebras: Gauge-invariant uniqueness theorem and the lattice of gauge-invariant ideals

Alexander Frei (University of Copenhagen)

14-Apr-2021, 19:00-20:00 (3 years ago)

Abstract: We start with an abstract definition of C*-correspondences comparing them to Fell bundles. After a first few basic results, we then swiftly move on to their representations. We introduce here the concept of covariances and relative Cuntz-Pimsner algebras.

From here we go into a detailed analysis of covariances within the category of C*-correpondences. We obtain here a systematic reduction leading us to a parametrisation of relative Cuntz-Pimsner algebras.

With this at hand we arrive at the gauge-invariant uniqueness theorem, for all (arbitrary) gauge-equivariant representations at once.

From here we move on to the analysis part of the program. We study the covariances in the case of the Fock representation and its quotients. As a result we derive that the parametrisation of relative Cuntz-Pimsner algebras is classifying. In other words, we obtain a complete and intrinsic picture of the lattice of quotients, and equivalently of gauge-invariant ideals.

If time permits, we finish off with the next chapter on their induced Fell bundles, as already investigated by Schweizer.

geometric topologynumber theoryoperator algebrasrepresentation theory

Audience: researchers in the topic

( slides | video )


Noncommutative Geometry in NYC

Series comments: Noncommutative Geometry studies an interplay between spatial forms and algebras with non-commutative multiplication. Our seminar welcomes talks in Number Theory, Geometric Topology and Representation Theory linked to the context of Operator Algebras. All talks are kept at the entry-level accessible to the graduate students and non-experts in the field. To join us click sju.webex.com/meet/nikolaei (5 min in advance) and igor DOT v DOT nikolaev AT gmail DOT com to subscribe/unsubscribe for the mailing list, to propose a talk or to suggest a speaker. Pending speaker's consent, we record and publish all talks at the hyperlink "video" on speaker's profile at the "Past talks" section. The slides can be posted by providing the organizers with a link in the format "myschool.edu/~myfolder/myslides.pdf". The duration of talks is 1 hour plus or minus 10 minutes.

Organizers: Alexander A. Katz, Igor V. Nikolaev*
*contact for this listing

Export talk to