Smooth Perturbations in Non-Reflexive Banach Spaces.
We show that every continuous derivation of a countably dominated Fréchet GB*-algebra A is spatial whenever A is additionally an AO*-algebra.
In this survey, we summarise some of the recent progress on the structure of spectral isometries between C*-algebras.
Dans cet article nous démontrons un théorème de stabilité des probabilités de retour sur un groupe localement compact unimodulaire, séparable et compactement engendré. Nous démontrons que le comportement asymptotique de F*(2n)(e) ne dépend pas de la densité F sous des hypothèses naturelles. A titre d’exemple nous établissons que la probabilité de retour sur une large classe de groupes résolubles se comporte comme exp(−n1/3).
Let ℳ be a von Neumann algebra with unit . Let τ be a faithful, normal, semifinite trace on ℳ. Given x ∈ ℳ, denote by the generalized s-numbers of x, defined by = inf||xe||: e is a projection in ℳ i with ≤ t (t ≥ 0). We prove that, if D is a complex domain and f:D → ℳ is a holomorphic function, then, for each t ≥ 0, is a subharmonic function on D. This generalizes earlier subharmonicity results of White and Aupetit on the singular values of matrices.
Let be a factor of type II or II having separable predual and let be the algebra of affiliated -measurable operators. We characterize the commutator space for sub-- bimodules and of .
Let A be a type II von Neumann algebra with predual A⁎. We prove that A⁎ does not have the alternative Dunford-Pettis property introduced by W. Freedman [7], i.e., there is a sequence (φₙ) converging weakly to φ in A⁎ with ||φₙ|| = ||φ|| = 1 for all n ∈ ℕ and a weakly null sequence (xₙ) in A such that φₙ(xₙ) ↛ 0. This answers a question posed in [7].
In this paper we consider a subset  of a Banach algebra A (containing all elements of A which have a generalized inverse) and characterize membership in the closure of the invertibles for the elements of Â. Thus our result yields a characterization of the closure of the invertible group for all those Banach algebras A which satisfy  = A. In particular, we prove that  = A when A is a von Neumann algebra. We also derive from our characterization new proofs of previously known results, namely Feldman...