32 citations · 48 across the 10 of their papers we have counts for
10 papers
Operator-valued maximal -divergences for completely positive maps
Rui Okayasu
We introduce an operator-valued maximal f-divergence for completely positive (CP) maps between von Neumann algebras, associated with an operator convex function f on (0,+infinity).…
Geometric mean and Lebesgue-type decomposition of completely positive maps
Rui Okayasu
We introduce the geometric mean and the parallel sum of completely positive (CP) maps between von Neumann algebras, based on the Pusz--Woronowicz theory of positive sesquilinear fo…
A note on injective factors with trivial bicentralizer
Rui Okayasu
We give an alternative proof that an injective factor on a Hilbert space with trivial bicentralizer is ITPFI. Our proof is given in parallel with each type of factors and it is bas…
Haagerup approximation property via bimodules
Rui Okayasu, Narutaka Ozawa, Reiji Tomatsu
The Haagerup approximation property (HAP) is defined for finite von Neumann algebras in such a way that the group von Neumann algebra of a discrete group has the HAP if and only if…
Generalisations of the Haagerup approximation property to arbitrary von Neumann algebras
Martijn Caspers, Rui Okayasu, Adam Skalski +1
The notion of the Haagerup approximation property, originally introduced for von Neumann algebras equipped with a faithful normal tracial state, is generalized to arbitrary von Neu…
Haagerup approximation property and positive cones associated with a von Neumann algebra
Rui Okayasu, Reiji Tomatsu
We introduce the notion of the -Haagerup approximation property for using a one-parameter family of positive cones studied by Araki and show that the -Haagerup…
Haagerup approximation property for arbitrary von Neumann algebras
Rui Okayasu, Reiji Tomatsu
We attempt presenting a notion of the Haagerup approximation property for an arbitrary von Neumann algebra by using its standard form. We also prove the expected heredity results f…
Free group -algebras associated with
Rui Okayasu
For every , we give a characterization of positive definite functions on a free group with finitely many generators, which can be extended to the positive linear functiona…
The ratio set of the harmonic measure of a random walk on a hyperbolic group
Masaki Izumi, Sergey Neshveyev, Rui Okayasu
We consider the harmonic measure on the Gromov boundary of a nonamenable hyperbolic group defined by a finite range random walk on the group, and study the corresponding orbit equi…
Cuntz-Krieger-Pimsner Algebras Associated with Amalgamated Free Product Groups
Rui Okayasu
We give a construction of a nuclear -algebra associated with an amalgamated free product of groups, generalizing Spielberg's construction of a certain Cuntz-Krieger algebra…