Sesquilinear and Quadratic Forms on Modules Over *-algebras
Some remarks about the three spaces problem in Banach algebras
Some seminorms on quasi *-algebras
Different types of seminorms on a quasi *-algebra (𝔄,𝔄₀) are constructed from a suitable family ℱ of sesquilinear forms on 𝔄. Two particular classes, extended C*-seminorms and CQ*-seminorms, are studied in some detail. A necessary and sufficient condition for the admissibility of a sesquilinear form in terms of extended C*-seminorms on (𝔄,𝔄₀) is given.
Spatiality of derivations of Fréchet GB*-algebras
We show that every continuous derivation of a countably dominated Fréchet GB*-algebra A is spatial whenever A is additionally an AO*-algebra.
Sur la continuité automatique des épimorphismes dans les -algèbres de Banach.
Sur un problème de I. Glicksberg : les idéaux fermés de type fini de
Soit , algèbre de convolution des mesures de Radon bornées sur le groupe abélien localement compact . Pour que soit fermé dans (ou, ce qui revient au même, pour que soit fermé), il faut et il suffit que soit la convolution d’une mesure inversible et d’une mesure idempotente.
Survey of some results in spectral theory obtained in Prague
Symmetric Banach *-algebras: invariance of spectrum
Let A be a Banach *-algebra which is a subalgebra of a Banach algebra B. In this paper, assuming that A is symmetric, various conditions are given which imply that A is inverse closed in B.