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Non-commutative martingale VMO-spaces

Narcisse Randrianantoanina (2009)

Studia Mathematica

We study Banach space properties of non-commutative martingale VMO-spaces associated with general von Neumann algebras. More precisely, we obtain a version of the classical Kadets-Pełczyński dichotomy theorem for subspaces of non-commutative martingale VMO-spaces. As application we prove that if ℳ is hyperfinite then the non-commutative martingale VMO-space associated with a filtration of finite-dimensional von Neumannn subalgebras of ℳ has property (u).

Noncommutative Poincaré recurrence theorem

Andrzej Łuczak (2001)

Colloquium Mathematicae

Poincaré’s classical recurrence theorem is generalised to the noncommutative setup where a measure space with a measure-preserving transformation is replaced by a von Neumann algebra with a weight and a Jordan morphism leaving the weight invariant. This is done by a suitable reformulation of the theorem in the language of L -space rather than the original measure space, thus allowing the replacement of the commutative von Neumann algebra L by a noncommutative one.

Noncommutative weak Orlicz spaces and martingale inequalities

Turdebek N. Bekjan, Zeqian Chen, Peide Liu, Yong Jiao (2011)

Studia Mathematica

This paper is devoted to the study of noncommutative weak Orlicz spaces and martingale inequalities. The Marcinkiewicz interpolation theorem is extended to include noncommutative weak Orlicz spaces as interpolation classes. As an application, we prove the weak type Φ-moment Burkholder-Gundy inequality for noncommutative martingales through establishing a weak type Φ-moment noncommutative Khinchin inequality for Rademacher random variables.

Non-equilibrium phase transitions, coherence and chaos

Geoffrey Sewell (1998)

Banach Center Publications

We present a scheme for the theory of phase transitions in open dissipative systems, and show that its demands are fulfilled by quantum stochastic models of open systems, such as the laser.

Nonlinear Lie-type derivations of von Neumann algebras and related topics

Ajda Fošner, Feng Wei, Zhankui Xiao (2013)

Colloquium Mathematicae

Motivated by the powerful and elegant works of Miers (1971, 1973, 1978) we mainly study nonlinear Lie-type derivations of von Neumann algebras. Let 𝓐 be a von Neumann algebra without abelian central summands of type I₁. It is shown that every nonlinear Lie n-derivation of 𝓐 has the standard form, that is, can be expressed as a sum of an additive derivation and a central-valued mapping which annihilates each (n-1)th commutator of 𝓐. Several potential research topics related to our work are also...

Non-normal elements in Banach *-algebras

B. Yood (2004)

Studia Mathematica

Let A be a Banach *-algebra with an identity, continuous involution, center Z and set of self-adjoint elements Σ. Let h ∈ Σ. The set of v ∈ Σ such that (h + iv)ⁿ is normal for no positive integer n is dense in Σ if and only if h ∉ Z. The case where A has no identity is also treated.

Non-orbit equivalent actions of 𝔽 n

Adrian Ioana (2009)

Annales scientifiques de l'École Normale Supérieure

For any 2 n , we construct a concrete 1-parameter family of non-orbit equivalent actions of the free group 𝔽 n . These actions arise as diagonal products between a generalized Bernoulli action and the action 𝔽 n ( 𝕋 2 , λ 2 ) , where 𝔽 n is seen as a subgroup of SL 2 ( ) .

Non-trivial derivations on commutative regular algebras.

A. F. Ber, Vladimir I. Chilin, Fyodor A. Sukochev (2006)

Extracta Mathematicae

Necessary and sufficient conditions are given for a (complete) commutative algebra that is regular in the sense of von Neumann to have a non-zero derivation. In particular, it is shown that there exist non-zero derivations on the algebra L(M) of all measurable operators affiliated with a commutative von Neumann algebra M, whose Boolean algebra of projections is not atomic. Such derivations are not continuous with respect to measure convergence. In the classical setting of the algebra S[0,1] of all...

Norm attaining bilinear forms on C*-algebras

J. Alaminos, R. Payá, A. R. Villena (2003)

Studia Mathematica

We give a sufficient condition on a C*-algebra to ensure that every weakly compact operator into an arbitrary Banach space can be approximated by norm attaining operators and that every continuous bilinear form can be approximated by norm attaining bilinear forms. Moreover we prove that the class of C*-algebras satisfying this condition includes the group C*-algebras of compact groups.

Normal cones and C * - m -convex structure

El Kinani, A., Mohamed Amine Nejjari, Mohamed Oudadess (2002)

Commentationes Mathematicae Universitatis Carolinae

The notion of normal cones is used to characterize C * - m -convex algebras among unital, symmetric and complete m -convex algebras.

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