Displaying similar documents to “Ascoli's theorem in almost quiet quasi-uniform space.”

On quasi-p-bounded subsets

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

Colloquium Mathematicae

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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 × P R K ( p ) ) ( B × P R K ( p ) ) = c l β X B × β ( ω ) , where P R K ( p ) is the set of Rudin-Keisler predecessors of p.

Bohr Cluster Points of Sidon Sets

L. Ramsey (1995)

Colloquium Mathematicae

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It is a long standing open problem whether Sidon subsets of ℤ can be dense in the Bohr compactification of ℤ ([LR]). Yitzhak Katznelson came closest to resolving the issue with a random process in which almost all sets were Sidon and and almost all sets failed to be dense in the Bohr compactification [K]. This note, which does not resolve this open problem, supplies additional evidence that the problem is delicate: it is proved here that if one has a Sidon set which clusters at even...

Pairwise monotonically normal spaces

Josefa Marín, Salvador Romaguera (1991)

Commentationes Mathematicae Universitatis Carolinae

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We introduce and study the notion of pairwise monotonically normal space as a bitopological extension of the monotonically normal spaces of Heath, Lutzer and Zenor. In particular, we characterize those spaces by using a mixed condition of insertion and extension of real-valued functions. This result generalizes, at the same time improves, a well-known theorem of Heath, Lutzer and Zenor. We also obtain some solutions to the quasi-metrization problem in terms of the pairwise monotone normality. ...

Continuity of projections of natural bundles

Włodzimierz M. Mikulski (1992)

Annales Polonici Mathematici

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This paper is a contribution to the axiomatic approach to geometric objects. A collection of a manifold M, a topological space N, a group homomorphism E: Diff(M) → Homeo(N) and a function π: N → M is called a quasi-natural bundle if (1) π ∘ E(f) = f ∘ π for every f ∈ Diff(M) and (2) if f,g ∈ Diff(M) are two diffeomorphisms such that f|U = g|U for some open subset U of M, then E(f)|π^{-1}(U) = E(g)|π^{-1}(U). We give conditions which ensure that π: N → M is continuous. In particular,...

Quasi-sums in several variables.

Maksa, Gyula, Nizsalóczki, Enikő (2006)

Acta Mathematica Academiae Paedagogicae Nyí regyháziensis. New Series [electronic only]

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