C*-algebras from actions of congruence monoids
Chris Bruce (University of Victoria)
Thursday 5th December, 2019 15:00-16:00 Maths 311B
Congruence monoids in the ring of integers are given by certain unions of arithmetic progressions. To each congruence monoid, there is a canonical way to associate a semigroup C*-algebra. I will explain this construction and then discuss joint work with Xin Li on K-theoretic invariants. I will also indicate how all of this generalizes to congruence monoids in the ring of integers of an arbitrary algebraic number field.