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Topologically Invertible Elements and Topological Spectrum

Mati Abel, Wiesław Żelazko (2006)

Bulletin of the Polish Academy of Sciences. Mathematics

Properties of topologically invertible elements and the topological spectrum of elements in unital semitopological algebras are studied. It is shown that the inversion x x - 1 is continuous in every invertive Fréchet algebra, and singly generated unital semitopological algebras have continuous characters if and only if the topological spectrum of the generator is non-empty. Several open problems are presented.

Topologies and bornologies determined by operator ideals, II

Ngai-Ching Wong (1994)

Studia Mathematica

Let be an operator ideal on LCS’s. A continuous seminorm p of a LCS X is said to be - continuous if Q ̃ p i n j ( X , X ̃ p ) , where X ̃ p is the completion of the normed space X p = X / p - 1 ( 0 ) and Q ̃ p is the canonical map. p is said to be a Groth()- seminorm if there is a continuous seminorm q of X such that p ≤ q and the canonical map Q ̃ p q : X ̃ q X ̃ p belongs to ( X ̃ q , X ̃ p ) . It is well known that when is the ideal of absolutely summing (resp. precompact, weakly compact) operators, a LCS X is a nuclear (resp. Schwartz, infra-Schwartz) space if and only if every continuous...

Topologies et bornologies nucléaires associées. Applications

Henri Hogbe-Nlend (1973)

Annales de l'institut Fourier

Le présent article est consacré à l’étude de la topologie nucléaire associée à une topologie localement convexe séparée arbitraire et ses applications. On utilise des techniques de Bornologie. On établit que tout espace ultra-bornologique, en particulier tout espace de Banach, est dual fort d’un espace nucléaire complet et on donne quelques applications de ce résultat. Nous montrons l’existence d’une large classe d’espaces nucléaires complets à bornés métrisables et à duals forts non nucléaires...

Topologies of compact families on the ideal space of a Banach algebra

Ferdinand Beckhoff (1996)

Studia Mathematica

Let be a family of compact sets in a Banach algebra A such that is stable with respect to finite unions and contains all finite sets. Then the sets U ( K ) : = I I d ( A ) : I K = , K ∈ define a topology τ() on the space Id(A) of closed two-sided ideals of A. is called normal if I i I in (Id(A),τ()) and x ∈ A╲I imply l i m i n f i x + I i > 0 . (1) If the family of finite subsets of A is normal then Id(A) is locally compact in the hull kernel topology and if moreover A is separable then Id(A) is second countable. (2) If the family of countable compact sets...

Topologies on central extensions of von Neumann algebras

Shavkat Ayupov, Karimbergen Kudaybergenov, Rauaj Djumamuratov (2012)

Open Mathematics

Given a von Neumann algebra M, we consider the central extension E(M) of M. We introduce the topology t c(M) on E(M) generated by a center-valued norm and prove that it coincides with the topology of local convergence in measure on E(M) if and only if M does not have direct summands of type II. We also show that t c(M) restricted to the set E(M)h of self-adjoint elements of E(M) coincides with the order topology on E(M)h if and only if M is a σ-finite type Ifin von Neumann algebra.

Topologies on the group of invertible transformations

Maciej Burnecki, Robert Rałowski (2011)

Banach Center Publications

We enlarge the amount of embeddings of the group G of invertible transformations of [0,1] into spaces of bounded linear operators on Orlicz spaces. We show the equality of the inherited coarse topologies.

Topologies on the space of ideals of a Banach algebra

Ferdinand Beckhoff (1995)

Studia Mathematica

Some topologies on the space Id(A) of two-sided and closed ideals of a Banach algebra are introduced and investigated. One of the topologies, namely τ , coincides with the so-called strong topology if A is a C*-algebra. We prove that for a separable Banach algebra τ coincides with a weaker topology when restricted to the space Min-Primal(A) of minimal closed primal ideals and that Min-Primal(A) is a Polish space if τ is Hausdorff; this generalizes results from [1] and [5]. All subspaces of Id(A)...

Topologies semi-vectorielles. Application à l'analyse complexe

Pierre Lelong (1975)

Annales de l'institut Fourier

On définit sur un espace vectoriel E une classe de topologies qui rendent la multiplication continue, mais ne sont pas vectorielles en général. Sur un espace complexe E elles permettent d’obtenir encore les principales propriétés des fonctions plurisousharmoniques. De telles topologies séparées sont localement pseudo-convexes (mais non localement convexes en général) : cette notion intervient dans les extensions données récemment par l’auteur du théorème de Banach-Steinhaus aux familles de polynômes...

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