Paper-folding models of the CAR algebra
- 👤 Speaker: Wilhelm Winter (Universität Münster)
- 📅 Date & Time: Thursday 17 July 2025, 09:30 - 10:10
- 📍 Venue: External
Abstract
I explain how the CAR algebra admits a Cantor spectrum C-diagonal that is not conjugate to its standard AF diagonal. This is done by classification theory of stably finite nuclear C-algebras, and the diagonal arises by realising the CAR algebra as the crossed product of a free and minimal action on the Cantor space, where the acting group is the product of a locally finite group with the infinite dihedral group. The main ingredient in the construction is a binary subshift associated to the well-known regular paper-folding sequence. The resulting diagonal pair has finite diagonal dimension, and upon taking tensor products one obtains countable many Cantor spectrum diagonals which are pairwise non-conjugate. This is joint work with Grigoris Kopsacheilis.
Series This talk is part of the Isaac Newton Institute Seminar Series series.
Included in Lists
- All CMS events
- bld31
- dh539
- External
- Featured lists
- INI info aggregator
- Isaac Newton Institute Seminar Series
- School of Physical Sciences
Note: Ex-directory lists are not shown.
![[Talks.cam]](/static/images/talkslogosmall.gif)

Wilhelm Winter (Universität Münster)
Thursday 17 July 2025, 09:30-10:10