Type semigroups of ample groupoids, and a purely-infinite/stably-finite dichotomy > 세미나

본문 바로가기
사이트 내 전체검색


세미나

모드선택 :              
세미나 신청은 모드에서 세미나실 사용여부를 먼저 확인하세요

Type semigroups of ample groupoids, and a purely-infinite/stably-finit…

이헌(2016-20245) 0 2619
구분 작용소
일정 2021-03-24 16:00 ~ 18:00
강연자 Aidan Sims (University of Wollongong)
기타
담당교수 이훈희
The notions of pure infiniteness and stable finiteness for C*-algebras were inspired by the Type decomposition of von Neumann algebras. But unlike the von Neumann case, we now know thanks to a remarkable example due to Rordam that even amongst simple, separable, nuclear C*-algebras there are examples that are neither stably finite nor purely infinite. Work of Rordam and Sierakowski (later built upon by Kirchberg and Sierakowski) showed how to investigate this dichotomy for crossed-product C*-algebras arising from group actions on the Cantor space K in terms of a “type semigroup” built from projections in C(K) modulo the relation induced by the group action. Ample groupoids generalise group actions on the Cantor set, and also incorporate constructions like inverse-semigroups, Cuntz-Krieger algebras, and partial actions. I will discuss work with Timothy Rainone on a dichotomy theorem for C*-algebras of ample groupoids using the idea of type semigroups. Very similar results were also obtained, completely independently, at almost exactly the same time by Bonicke and Li, who deserve full credit for their work.

세미나명

   

상단으로

Research Institute of Mathematics
서울특별시 관악구 대학동 서울대학교 자연과학대학 129동 305호
Tel. 02-880-6562 / Fax. 02-877-6541 su305@snu.ac.kr

COPYRIGHT ⓒ 자연과학대학 수학연구소 ALL RIGHT RESERVED.