Radicals, crossed products, and flows
Range of a contractive strongly positive projection in a C*-algebra
We generalize a result of Choi and Effros on the range of a contractive completely positive projection in a C*-algebra to the case when this projection is only strongly positive using, moreover, an elementary argument instead of a 2×2-matrix technique.
Reflective-coreflective equivalence.
Reflexive Operator Algebras on Non-Commutative Hardy Spaces.
Regular AF subalgebras of some crossed products.
Relatively independent joinings and subsystems of W*-dynamical systems
Relatively independent joinings of W*-dynamical systems are constructed. This is intimately related to subsystems of W*-dynamical systems, and therefore we also study general properties of subsystems, in particular fixed point subsystems and compact subsystems. This allows us to obtain characterizations of weak mixing and relative ergodicity, as well as of certain compact subsystems, in terms of joinings.
Remarks on a C*-dynamical system.
Remarks on the Fixed-Point Algebras of Product Type Actions.
Restrictions of CP-semigroups to maximal commutative subalgebras
We give a necessary and sufficient criterion for a normal CP-map on a von Neumann algebra to admit a restriction to a maximal commutative subalgebra. We apply this result to give a far reaching generalization of Rebolledo's sufficient criterion for the Lindblad generator of a Markov semigroup on ℬ(G).
Rieffel’s pseudodifferential calculus and spectral analysis of quantum Hamiltonians
We use the functorial properties of Rieffel’s pseudodifferential calculus to study families of operators associated to topological dynamical systems acted by a symplectic space. Information about the spectra and the essential spectra are extracted from the quasi-orbit structure of the dynamical system. The semi-classical behavior of the families of spectra is also studied.