EuDML | Browse

In this paper we introduce and study new concepts of convergence and adherent points for fuzzy filters and fuzzy nets in the light of the $Q$ -relation and the $Q$ -neighborhood of fuzzy points due to Pu and Liu [28]. As applications of these concepts we give several new characterizations of the closure of fuzzy sets, fuzzy Hausdorff spaces, fuzzy continuous mappings and strong $Q$ -compactness. We show that there is a relation between the convergence of fuzzy filters and the convergence of fuzzy nets similar...

On convergences of signed states

Anatolij Dvurečenskij (1978)

Mathematica Slovaca

On $E$ -sequentially regular spaces

Roman Frič (1976)

Czechoslovak Mathematical Journal

On fuzzy function spaces.

Jäger, Gunther (1999)

International Journal of Mathematics and Mathematical Sciences

On ideal equal convergence

Rafał Filipów, Marcin Staniszewski (2014)

Open Mathematics

We consider ideal equal convergence of a sequence of functions. This is a generalization of equal convergence introduced by Császár and Laczkovich [Császár Á., Laczkovich M., Discrete and equal convergence, Studia Sci. Math. Hungar., 1975, 10(3–4), 463–472]. Our definition of ideal equal convergence encompasses two different kinds of ideal equal convergence introduced in [Das P., Dutta S., Pal S.K., On and *-equal convergence and an Egoroff-type theorem, Mat. Vesnik, 2014, 66(2), 165–177]_and [Filipów...

On idempotent filters

Miroslav Katětov (1977)

Časopis pro pěstování matematiky

On local merotopic character

Petr Simon (1971)

Commentationes Mathematicae Universitatis Carolinae

On mappings preserving a family of star bodies.

Sójka, Grzegorz (2003)

Beiträge zur Algebra und Geometrie

On meager function spaces, network character and meager convergence in topological spaces

Taras O. Banakh, Volodymyr Mykhaylyuk, Lubomyr Zdomsky (2011)

Commentationes Mathematicae Universitatis Carolinae

For a non-isolated point $x$ of a topological space $X$ let ${nw}_{χ} (x)$ be the smallest cardinality of a family $𝒩$ of infinite subsets of $X$ such that each neighborhood $O (x) \subset X$ of $x$ contains a set $N \in 𝒩$ . We prove that (a) each infinite compact Hausdorff space $X$ contains a non-isolated point $x$ with ${nw}_{χ} (x) = ℵ_{0}$ ; (b) for each point $x \in X$ with ${nw}_{χ} (x) = ℵ_{0}$ there is an injective sequence ${(x_{n})}_{n \in ω}$ in $X$ that $ℱ$ -converges to $x$ for some meager filter $ℱ$ on $ω$ ; (c) if a functionally Hausdorff space $X$ contains an $ℱ$ -convergent injective sequence for some meager filter...

On metrization of hyperspaces

Flachsmeyer, Jürgen (1977)

Abstracta. 5th Winter School on Abstract Analysis

On monotone and pointwise splittability

Lj. Kočinac (1991)

Matematički Vesnik

On Nets and Filters.

J.F. Aarnes, P.R. Andenaes (1972)

Mathematica Scandinavica

On plane topologies with high sequential order

Roman Frič (1990)

Commentationes Mathematicae Universitatis Carolinae

On quasi-p-bounded subsets

M. Sanchis, A. Tamariz-Mascarúa (1999)

Colloquium Mathematicae

The notion of quasi-p-boundedness for p ∈ $ω^{*}$ is introduced and investigated. We characterize quasi-p-pseudocompact subsets of β(ω) containing ω, and we show that the concepts of RK-compatible ultrafilter and P-point in $ω^{*}$ can be defined in terms of quasi-p-pseudocompactness. For p ∈ $ω^{*}$ , we prove that a subset B of a space X is quasi-p-bounded in X if and only if B × $P_{R K} (p)$ is bounded in X × $P_{R K} (p)$ , if and only if $c l_{β (X \times P_{R K} (p))} (B \times P_{R K} (p)) = c l_{β X} B \times β (ω)$ , where $P_{R K} (p)$ is the set of Rudin-Keisler predecessors of p.

On spaces with the ideal convergence property

Jakub Jasinski, Ireneusz Recław (2008)

Colloquium Mathematicae

Let I ⊆ P(ω) be an ideal. We continue our investigation of the class of spaces with the I-ideal convergence property, denoted (I). We show that if I is an analytic, non-countably generated P-ideal then (I) ⊆ s₀. If in addition I is non-pathological and not isomorphic to $I_{b}$ , then (I) spaces have measure zero. We also present a characterization of the (I) spaces using clopen covers.

Currently displaying 141 – 160 of 307

Previous Page 8 Next