S-Space College of Natural Sciences (자연과학대학) Dept. of Mathematical Sciences (수리과학부) Theses (Ph.D. / Sc.D._수리과학부)
Noncommutative tori and their crossed products by finite groups
비가환 원환체와 유한군에 의한 교차곱
- 자연과학대학 수리과학부
- Issue Date
- 서울대학교 대학원
- 학위논문 (박사)-- 서울대학교 대학원 : 수리과학부, 2015. 2. 정자아.
- We study canonical group actions on higher dimensional noncommutative tori which generalize the SL2(Z) actions on 2-dimensional noncommutative tori, namely, rotation algebras and show that the crossed products of higher
dimensional simple tori by canonical actions of finite groups are not necessarily AF algebras but AT algebras. This result on non-AF crossed products is contrasted with the recently known fact that the crossed products
of irrational rotation algebras by finite subgroups of SL2(Z) are always AF aglebras.