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Displaying 181 – 200 of 1528

On analyticity in cosmic spaces

Oleg Okunev (1993)

Commentationes Mathematicae Universitatis Carolinae

We prove that a cosmic space (= a Tychonoff space with a countable network) is analytic if it is an image of a $K$ -analytic space under a measurable mapping. We also obtain characterizations of analyticity and $σ$ -compactness in cosmic spaces in terms of metrizable continuous images. As an application, we show that if $X$ is a separable metrizable space and $Y$ is its dense subspace then the space of restricted continuous functions $C_{p} (X ∣ Y)$ is analytic iff it is a $K_{σ δ}$ -space iff $X$ is $σ$ -compact.

On AP and WAP spaces

Angelo Bella, Ivan V. Yashchenko (1999)

Commentationes Mathematicae Universitatis Carolinae

Several remarks on the properties of approximation by points (AP) and weak approximation by points (WAP) are presented. We look in particular at their behavior in product and at their relationships with radiality, pseudoradiality and related concepts. For instance, relevant facts are: (a) There is in ZFC a product of a countable WAP space with a convergent sequence which fails to be WAP. (b) $C_{p}$ over $σ$ -compact space is AP. Therefore AP does not imply even pseudoradiality in function spaces, while...

On AP spaces in concern with compact-like sets and submaximality

Mi Ae Moon, Myung Hyun Cho, Junhui Kim (2011)

Commentationes Mathematicae Universitatis Carolinae

The definitions of AP and WAP were originated in categorical topology by A. Pultr and A. Tozzi, Equationally closed subframes and representation of quotient spaces, Cahiers Topologie Géom. Différentielle Catég. 34 (1993), no. 3, 167-183. In general, we have the implications: $T_{2} \Rightarrow K C \Rightarrow U S \Rightarrow T_{1}$ , where $K C$ is defined as the property that every compact subset is closed and $U S$ is defined as the property that every convergent sequence has at most one limit. And a space is called submaximal if every dense subset is open....

On Applications of Bing-Krasinkiewicz-Lelek Maps

Eiichi Matsuhashi (2007)

Bulletin of the Polish Academy of Sciences. Mathematics

We characterize Peano continua using Bing-Krasinkiewicz-Lelek maps. Also we deal with some topics on Whitney preserving maps.

On approximate fuzzy maps.

Salih, Haval Mahmood Mohammed, Borumand Saeid, A. (2010)

Acta Universitatis Apulensis. Mathematics - Informatics

On approximate inverse systems and resolutions

Sibe Mardešić (1993)

Fundamenta Mathematicae

On approximate n-connectedness

Thomas Sanders (1983)

Fundamenta Mathematicae

On approximately semiopen maps in topological spaces.

Caldas, Miguel, Saraf, Ratnesh K. (2006)

Divulgaciones Matemáticas

On approximation by step multifunctions without compactness conditions

Andrzej Spakowski (1990)

Časopis pro pěstování matematiky

On approximation of Baire functions by Darboux functions

Jaroslav Smítal (1971)

Czechoslovak Mathematical Journal

On approximation of homeomorphisms of a Cantor set

Konstantin Medynets (2007)

Fundamenta Mathematicae

We continue the study of topological properties of the group Homeo(X) of all homeomorphisms of a Cantor set X with respect to the uniform topology τ, which was started by Bezuglyi, Dooley, Kwiatkowski and Medynets. We prove that the set of periodic homeomorphisms is τ-dense in Homeo(X) and deduce from this result that the topological group (Homeo(X),τ) has the Rokhlin property, i.e., there exists a homeomorphism whose conjugacy class is τ-dense in Homeo(X). We also show that for any homeomorphism...

On approximation of multifunctions with respect to the Vietoris topology

Andrzej Spakowski (1988)

Acta Universitatis Carolinae. Mathematica et Physica

On ARU-resolutions of uniform spaces.

Baladze, V. (2003)

Georgian Mathematical Journal

On Asymmetric Distances

Andrea C.G. Mennucci (2013)

Analysis and Geometry in Metric Spaces

In this paper we discuss asymmetric length structures and asymmetric metric spaces. A length structure induces a (semi)distance function; by using the total variation formula, a (semi)distance function induces a length. In the first part we identify a topology in the set of paths that best describes when the above operations are idempotent. As a typical application, we consider the length of paths defined by a Finslerian functional in Calculus of Variations. In the second part we generalize the...

On atomic ideals in some factor rings of $C (X, ℤ)$

Alireza Olfati (2021)

Commentationes Mathematicae Universitatis Carolinae

A nonzero $R$ -module $M$ is atomic if for each two nonzero elements $a, b$ in $M$ , both cyclic submodules $R a$ and $R b$ have nonzero isomorphic submodules. In this article it is shown that for an infinite $P$ -space $X$ , the factor rings $C (X, ℤ) / C_{F} (X, ℤ)$ and $C_{c} (X) / C_{F} (X)$ have no atomic ideals. This fact generalizes a result published in paper by A. Mozaffarikhah, E. Momtahan, A. R. Olfati and S. Safaeeyan (2020), which says that for an infinite set $X$ , the factor ring $ℤ^{X} / ℤ^{(X)}$ has no atomic ideal. Another result is that for each infinite $P$ -space $X$ , the...

Currently displaying 181 – 200 of 1528

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Displaying 181 – 200 of 1528

On analyticity in cosmic spaces

On AP and WAP spaces

On AP spaces in concern with compact-like sets and submaximality

On Applications of Bing-Krasinkiewicz-Lelek Maps

On approximate fuzzy maps.

On approximate inverse systems and resolutions

On approximate n-connectedness

On approximately semiopen maps in topological spaces.

On approximation by step multifunctions without compactness conditions

On approximation of Baire functions by Darboux functions

On approximation of homeomorphisms of a Cantor set

On approximation of multifunctions with respect to the Vietoris topology

On ARU-resolutions of uniform spaces.

On Asymmetric Distances

On atomic ideals in some factor rings of $C (X, ℤ)$

On atomic mappings

On Aumann's theorem that the circle does not admit a mean

On $b$ - $I$ -open sets and $b$ - $I$ -continuous functions.

On $b$ -open setes.

On $B$ -spaces

Currently displaying 181 – 200 of 1528