Results 31 to 40 of about 60 (60)
Preimages of ultrafilters need not extend to ultrafilters in ZF
, 2020 We construct a permutation model M with a set of atoms A and an onto function f : A → ω such that A and ω have free ultrafilters but that for each free ultrafilter on ω its preimage under f does not extend to an ultrafilter on A.
Paul Howard +2 more
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© Hindawi Publishing Corp. QUANTIFICATION OF TOPOLOGICAL CONCEPTS USING IDEALS
, 2000 . We introduce certain ideals of real-valued functions as a natural generalization of filters. We show that these ideals establish a canonical framework for the quantification of topological concepts, such as closedness, adherence, and compactness, in ...
Robert Lowen, Bart Windels
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, 2004 It is shown that the categories of stably continuous σ-frames and compact regular σ-biframes are equivalent. This is the analogue of Banaschewski and Brümmer [1], linking the stably continuous frames and compact regular biframes ...
Matutu, Phethiwe
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, 2017 Let C(K) denote the Banach space of all (real or complex) continuous functions on a compact Hausdorff space K. We present a novel point of view on the classical Arzela-Ascoli theorem: For every pointwise bounded and equicontinuous subset F of C(K) there ...
Wojtowicz, Marek
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On some parallelism between complete regularity and zero-dimensionality
, 2018 We explore some parallelism between the categories CRFrm and 0DFrm of completely regular frames and zero-dimensional frames, respectively, with a view to establishing zero-dimensional analogues of C*-quotients.
Ighedo, Oghenetega, Mugochi, Martin M.
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The Topological Universe Of Locally Precompact Semiuniform Convergence Spaces
, 1996 . The importance of local precompactness has become apparent in theorems of the Ascoli type proved by Bentley and Herrlich [3] in the realm of filter spaces as well as by Wyler [14] in the realm of uniform limit spaces.
Gerhard Preuß
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Compactness with respect to a convergence structure
, 2004 A convergence structure for a category is given by determining convergent nets and their limits for each object of this category under validity of some basic convergence axioms.
Šlapal, Josef
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, 1997 . Semiuniform convergence spaces form a common generalization of (symmetric) limit spaces (and thus of symmetric topological spaces) as well as of uniform limit spaces (and thus of uniform spaces) with many convenient properties such as cartesian ...
Gerhard Preu, Gerhard Preuß
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Псевдокомпактни полу-топологични групи
, 2012 Митрофан М. Чобан, Петър Ст. Кендеров, Уорън Б. Муурс - Полу-топологична група (съответно, топологична група) е група, снабдена с топология, относно която груповата оперция произведение е частично непрекъсната по всяка от променливите (съответно ...
Kenderov, Petar +2 more
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On lightly and countably compact spaces in ZF
, 2019 Given a topological space X = (X, T), we show in the Zermelo-Fraenkel set theory ZF that:(i) Every locally finite family of open sets of X is finite iff every pairwise disjoint, locally finite family of open sets is finite.(ii) Every locally finite ...
Keremedis, Kyriakos
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