Displaying 141 – 160 of 307

Showing per page

Relationship among various Vietoris-type and microsimplicial homology theories

Takuma Imamura (2021)

Archivum Mathematicum

In this paper, we clarify the relationship among the Vietoris-type homology theories and the microsimplicial homology theories, where the latter are nonstandard homology theories defined by M.C. McCord (for topological spaces), T. Korppi (for completely regular topological spaces) and the author (for uniform spaces). We show that McCord’s and our homology are isomorphic for all compact uniform spaces and that Korppi’s and our homology are isomorphic for all fine uniform spaces. Our homology shares...

Relative Compactness for Hyperspaces

Sianesi, Francesca (1999)

Serdica Mathematical Journal

The present paper contains results characterizing relatively compact subsets of the space of the closed subsets of a metrizable space, equipped with various hypertopologies. We investigate the hyperspace topologies that admit a representation as weak topologies generated by families of gap functionals defined on closed sets, as well as hit-and-miss topologies and proximal-hit and-miss topologies.

Relative normality and product spaces

Takao Hoshina, Ryoken Sokei (2003)

Commentationes Mathematicae Universitatis Carolinae

Arhangel’skiĭ defines in [Topology Appl. 70 (1996), 87–99], as one of various notions on relative topological properties, strong normality of A in X for a subspace A of a topological space X , and shows that this is equivalent to normality of X A , where X A denotes the space obtained from X by making each point of X A isolated. In this paper we investigate for a space X , its subspace A and a space Y the normality of the product X A × Y in connection with the normality of ( X × Y ) ( A × Y ) . The cases for paracompactness, more...

Relative symmetrizability and metrizability

Aleksander V. Arhangel'skii, I. Ju. Gordienko (1996)

Commentationes Mathematicae Universitatis Carolinae

Relative metrizability is defined and connections with other relative properties are established.

Relatively coarse sequential convergence

Roman Frič, Fabio Zanolin (1997)

Czechoslovak Mathematical Journal

We generalize the notion of a coarse sequential convergence compatible with an algebraic structure to a coarse one in a given class of convergences. In particular, we investigate coarseness in the class of all compatible convergences (with unique limits) the restriction of which to a given subset is fixed. We characterize such convergences and study relative coarseness in connection with extensions and completions of groups and rings. E.g., we show that: (i) each relatively coarse dense group precompletion...

Relatively compact spaces and separation properties

Aleksander V. Arhangel'skii, Ivan V. Yashchenko (1996)

Commentationes Mathematicae Universitatis Carolinae

We consider the property of relative compactness of subspaces of Hausdorff spaces. Several examples of relatively compact spaces are given. We prove that the property of being a relatively compact subspace of a Hausdorff spaces is strictly stronger than being a regular space and strictly weaker than being a Tychonoff space.

Relatively complete ordered fields without integer parts

Mojtaba Moniri, Jafar S. Eivazloo (2003)

Fundamenta Mathematicae

We prove a convenient equivalent criterion for monotone completeness of ordered fields of generalized power series [ [ F G ] ] with exponents in a totally ordered Abelian group G and coefficients in an ordered field F. This enables us to provide examples of such fields (monotone complete or otherwise) with or without integer parts, i.e. discrete subrings approximating each element within 1. We include a new and more straightforward proof that [ [ F G ] ] is always Scott complete. In contrast, the Puiseux series field...

Relatively maximal convergences

Szymon Dolecki, Michel Pillot (1998)

Bollettino dell'Unione Matematica Italiana

Topologie, pretopologie, paratopologie e pseudotopologie sono importanti classi di convergenze, chiuse per estremi superiori (superiormente chiuse) ed inoltre caratterizzabili mediante le aderenze di certi filtri. Convergenze J -massimali in una classe superiormente chiusa D J , cioè massimali fra le D -convergenze aventi la stessa imagine per la proiezione su J , svolgono un ruolo importante nella teoria dei quozienti; infatti, una mappa J -quoziente sulla convergenza J -massimale in D è automaticamente...

Relatively minimal extensions of topological flows

Mieczysław Mentzen (2000)

Colloquium Mathematicae

The concept of relatively minimal (rel. min.) extensions of topological flows is introduced. Several generalizations of properties of minimal extensions are shown. In particular the following extensions are rel. min.: distal point transitive, inverse limits of rel. min., superpositions of rel. min. Any proximal extension of a flow Y with a dense set of almost periodic (a.p.) points contains a unique subflow which is a relatively minimal extension of Y. All proximal and distal factors of a point...

Currently displaying 141 – 160 of 307