No CrossRef data available.
Published online by Cambridge University Press: 19 September 2008
Let
be a C*-algebra and τ:G → Aut
a compact abelian action such that the fixed point algebra
τ is simple. Denote by
F the *-subalgebra of G-finite elements. Let H:
F →
be a *-operator commuting with τ such that
and the matrix inequality

holds for all finite sequences X1, …, Xn in
F. Then H is closable, and the closure
is the generator of a strongly continuous semigroup {exp (−t
): t ≥ 0} of completely positive contractions. Furthermore, there exists a convolution semigroup {μt: t ≥ 0} of probability measures on G such that
.
This result has various extensions and refinements.