One-parameter automorphism groups of operator algebras allowing spectral projections

Examples of one-parameter automorphism groups of UHF algebras

B. Blackadar [1] constructed for the first time an example of a symmetry (or an automorphism of period two) of the CAR algebra (or the UHF algebra of type 2) whose fixed point algebra is not AF (or approximately finite-dimensional). This was soon extended to produce an example of finite-group actions on UHF algebras whose fixed point algebras are not AF [5] and then of compact-group actions [12...

Compact automorphism groups of vertex operator algebras

Let V be a simple vertex operator algebra which admits the continuous, faithful action of a compact Lie group G of automorphisms. We establish a Schur-Weyl type duality between the unitary, irreducible modules for G and the irreducible modules for V G which are contained in V where V G is the space of G-invariants of V. We also prove a concomitant Galois correspondence between vertex operator s...

On the Spectral Type of One-parameter Groups on Operator Algebras1

We show that two unitary representations of R of very different spectral type can give rise to the same one-parameter group of "-automorphisms of a C*-algebra. Arveson [1] has introduced a spectral theory for automorphism groups on C*-algebras. However, little seems to be known about the spectral type of such groups. The fact that two unitary representations of R of very different spectral prop...

On Automorphism Groups of C*-algebras

Images of contractive projections on operator algebras

It is shown that if P is a weak∗-continuous contractive projection on a JBW∗-triple M , then P(M) is of type I or semifinite, respectively, if M is of the corresponding type. We also show that P(M) has no infinite spin part if M is a type I von Neumann algebra.  2002 Elsevier Science (USA). All rights reserved.