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Closed subgroups in Banach spaces

Fredric Ancel, Tadeusz Dobrowolski, Janusz Grabowski (1994)

Studia Mathematica

We show that zero-dimensional nondiscrete closed subgroups do exist in Banach spaces E. This happens exactly when E contains an isomorphic copy of c 0 . Other results on subgroups of linear spaces are obtained.

Coarse dimensions and partitions of unity.

N. Brodskiy, J. Dydak (2008)

RACSAM

Gromov and Dranishnikov introduced asymptotic and coarse dimensions of proper metric spaces via quite different ways. We define coarse and asymptotic dimension of all metric spaces in a unified manner and we investigate relationships between them generalizing results of Dranishnikov and Dranishnikov-Keesling-Uspienskij.

Colorings of Periodic Homeomorphisms

Yuji Akaike, Naotsugu Chinen, Kazuo Tomoyasu (2009)

Bulletin of the Polish Academy of Sciences. Mathematics

We calculate the exact value of the color number of a periodic homeomorphism without fixed points on a finite connected graph.

Combinatorial trees in Priestley spaces

Richard N. Ball, Aleš Pultr, Jiří Sichler (2005)

Commentationes Mathematicae Universitatis Carolinae

We show that prohibiting a combinatorial tree in the Priestley duals determines an axiomatizable class of distributive lattices. On the other hand, prohibiting n -crowns with n 3 does not. Given what is known about the diamond, this is another strong indication that this fact characterizes combinatorial trees. We also discuss varieties of 2-Heyting algebras in this context.

Compact pospaces

Venu G. Menon (2003)

Commentationes Mathematicae Universitatis Carolinae

Posets with property DINT which are compact pospaces with respect to the interval topologies are characterized.

Compact spaces that do not map onto finite products

Antonio Avilés (2009)

Fundamenta Mathematicae

We provide examples of nonseparable compact spaces with the property that any continuous image which is homeomorphic to a finite product of spaces has a maximal prescribed number of nonseparable factors.

Compactifications of ℕ and Polishable subgroups of S

Todor Tsankov (2006)

Fundamenta Mathematicae

We study homeomorphism groups of metrizable compactifications of ℕ. All of those groups can be represented as almost zero-dimensional Polishable subgroups of the group S . As a corollary, we show that all Polish groups are continuous homomorphic images of almost zero-dimensional Polishable subgroups of S . We prove a sufficient condition for these groups to be one-dimensional and also study their descriptive complexity. In the last section we associate with every Polishable ideal on ℕ a certain Polishable...

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