Displaying similar documents to “Ultra-b-barrelled spaces and the completeness of L b ( E , F )

On topological groups with a small base and metrizability

Saak Gabriyelyan, Jerzy Kąkol, Arkady Leiderman (2015)

Fundamenta Mathematicae

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A (Hausdorff) topological group is said to have a -base if it admits a base of neighbourhoods of the unit, U α : α , such that U α U β whenever β ≤ α for all α , β . The class of all metrizable topological groups is a proper subclass of the class T G of all topological groups having a -base. We prove that a topological group is metrizable iff it is Fréchet-Urysohn and has a -base. We also show that any precompact set in a topological group G T G is metrizable, and hence G is strictly angelic. We deduce from...

On the Hausdorff Dimension of Topological Subspaces

Tomasz Szarek, Maciej Ślęczka (2006)

Bulletin of the Polish Academy of Sciences. Mathematics

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It is shown that every Polish space X with d i m T X d admits a compact subspace Y such that d i m H Y d where d i m T and d i m H denote the topological and Hausdorff dimensions, respectively.

Linear topological properties of the Lumer-Smirnov class of the polydisc

Marek Nawrocki (1992)

Studia Mathematica

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Linear topological properties of the Lumer-Smirnov class L N ( n ) of the unit polydisc n are studied. The topological dual and the Fréchet envelope are described. It is proved that L N ( n ) has a weak basis but it is nonseparable in its original topology. Moreover, it is shown that the Orlicz-Pettis theorem fails for L N ( n ) .

Remarks on flat and differential K -theory

Man-Ho Ho (2014)

Annales mathématiques Blaise Pascal

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In this note we prove some results in flat and differential K -theory. The first one is a proof of the compatibility of the differential topological index and the flat topological index by a direct computation. The second one is the explicit isomorphisms between Bunke-Schick differential K -theory and Freed-Lott differential K -theory.

Nonnormality of remainders of some topological groups

Aleksander V. Arhangel'skii, J. van Mill (2016)

Commentationes Mathematicae Universitatis Carolinae

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It is known that every remainder of a topological group is Lindelöf or pseudocompact. Motivated by this result, we study in this paper when a topological group G has a normal remainder. In a previous paper we showed that under mild conditions on G , the Continuum Hypothesis implies that if the Čech-Stone remainder G * of G is normal, then it is Lindelöf. Here we continue this line of investigation, mainly for the case of precompact groups. We show that no pseudocompact group, whose weight...

Remarks on 𝒮 -Closedness in Topological Spaces

Zbigniew Duszyński (2007)

Bollettino dell'Unione Matematica Italiana

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Corresponding to [27], some properties of S-closed subspaces and subsets 𝒮 -closed relative to a topological space are proved. Conditions under which mappings preserve certain 𝒮 -closed subspaces are investigated.

Interplay between strongly universal spaces and pairs

Taras Banakh, Robert Cauty

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Given a pair (M,X) of spaces we investigate the connections between the (strong) universality of (M,X) and that of the space X. We apply this to prove Enlarging, Deleting, and Strong Negligibility Theorems for strongly universal and absorbing spaces. Given an absorbing space Ω we also study the question of topological uniqueness of the pair (M,X), where M = [ 0 , 1 ] ω or M = ( 0 , 1 ) ω and X is a copy of Ω in M having a locally homotopy negligible complement in M.

Spaces of continuous step functions over LOTS

Raushan Z. Buzyakova (2006)

Fundamenta Mathematicae

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We investigate spaces C p ( · , n ) over LOTS (linearly ordered topological spaces). We find natural necessary conditions for linear Lindelöfness of C p ( · , n ) over LOTS. We also characterize countably compact LOTS whose C p ( · , n ) is linearly Lindelöf for each n. Both the necessary conditions and the characterization are given in terms of the topology of the Dedekind completion of a LOTS.