On the structure of derivations on certain nonamenable nuclear Banach algebras.
On the structure of Jordan *-derivations
On the structure of rank one elements in Banach algebras.
On the ultrametric Stone-Weierstrass theorem and Mahler's expansion
We describe an ultrametric version of the Stone-Weierstrass theorem, without any assumption on the residue field. If is a subset of a rank-one valuation domain , we show that the ring of polynomial functions is dense in the ring of continuous functions from to if and only if the topological closure of in the completion of is compact. We then show how to expand continuous functions in sums of polynomials.
On the uniform boundedness of elements of the type in Hermitian lmc-algebras
On the weak amenability of ℬ(X)
We investigate the weak amenability of the Banach algebra ℬ(X) of all bounded linear operators on a Banach space X. Sufficient conditions are given for weak amenability of this and other Banach operator algebras with bounded one-sided approximate identities.
On topological algebra sheaves of a nuclear type
On topological algebras
On Topological Divisors of Zero in Topological Algebras
On topological modules and duality
On topologically nilpotent algebras
On topologizable algebras
On topologization of countably generated algebras
We prove that any real or complex countably generated algebra has a complete locally convex topology making it a topological algebra. Assuming the continuum hypothesis, it is the best possible result expressed in terms of the cardinality of a set of generators. This result is a corollary to a theorem stating that a free algebra provided with the maximal locally convex topology is a topological algebra if and only if the number of variables is at most countable. As a byproduct we obtain an example...
On Uniform Continuity of the Spectral Radius in Banach Algebras.
On unitary convex decompositions of vectors in a -algebra
By exploiting his recent results, the author further investigates the extent to which variation in the coefficients of a unitary convex decomposition of a vector in a unital -algebra permits the vector decomposable as convex combination of fewer unitaries; certain -algebra results due to M. Rørdam have been extended to the general setting of -algebras.
On unitary equivalence of quasi-free Hilbert modules
We characterize unitary equivalence of quasi-free Hilbert modules, which complements Douglas and Misra's earlier work [New York J. Math. 11 (2005)]. We first confine our arguments to the classical setting of reproducing Hilbert spaces and then relate our result to equivalence of Hermitian vector bundles.
On vector spaces and algebras with maximal locally pseudoconvex topologies
Let X be a real or complex vector space. We show that the maximal p-convex topology makes X a complete Hausdorff topological vector space. If X has an uncountable dimension, then different p give different topologies. However, if the dimension of X is at most countable, then all these topologies coincide. This leads to an example of a complete locally pseudoconvex space X that is not locally convex, but all of whose separable subspaces are locally convex. We apply these results to topological algebras,...
On Α Bochner΄s Type Theorem in Topological Algebras
One-sided division absolute valued algebras.
We develop a structure theory for left divsion absolute valued algebras which shows, among other things, that the norm of such an algebra comes from an inner product. Moreover, we prove the existence of left division complete absolute valued algebras with left unit of arbitrary infinite hilbertian division and with the additional property that they have nonzero proper closed left ideals. Our construction involves results from the representation theory of the so called "Canonical Anticommutation...
Operator Connes-amenability of completely bounded multiplier Banach algebras
For a completely contractive Banach algebra , we find conditions under which the completely bounded multiplier algebra is a dual Banach algebra and the operator amenability of is equivalent to the operator Connes-amenability of . We also show that, in this case, these are equivalent to the existence of a normal virtual operator diagonal.