Examples of one-parameter automorphism groups of UHF algebras

Abstract

Examples of (strongly continuous) one-parameter groups of automorphisms of UHF C*-algebras are given. One example has the property that the infinitesimal generator does not have a union of finite-dimensional subalgebras as a core. (This solves the so-called core problem, raised by S. Sakai, in the negative.) The other has the property of not being classical or commutative, i.e., the one-parameter group is not just an inner perturbation of a one-parameter group which has an increasing sequence of invariant finite-dimensional subalgebras with dense union. (This was certainly expected but has not been proven explicitly.)