Displaying similar documents to “A universal non-compact operator”

On universal composition of maps.

Zvonko Cerin (1991)

Publicacions Matemàtiques

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In this paper we shall introduce notions of F-universality and F-e-universality for maps between compact Hausdorff spaces and explore the behaviour of these properties under the operation of composition of maps. We consider both the quest for conditions on maps f and g which would imply that their composition g o f is either F-universal or F-e-universal and the quest for consequences on f and g when the composition g o f is either F-universal or F-e-universal. In our approach F is an...

Universal functions

Paul B. Larson, Arnold W. Miller, Juris Steprāns, William A. R. Weiss (2014)

Fundamenta Mathematicae

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A function of two variables F(x,y) is universal if for every function G(x,y) there exist functions h(x) and k(y) such that G(x,y) = F(h(x),k(y)) for all x,y. Sierpiński showed that assuming the Continuum Hypothesis there exists a Borel function F(x,y) which is universal. Assuming Martin's Axiom there is a universal function of Baire class 2. A universal function cannot be of Baire class 1. Here we show that it is consistent that for each α with 2 ≤ α...

Countable-dimensional spaces: a survey

Ryszard Engelking, Elżbieta Pol

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CONTENTS1. Definitions and characterizations ...................................................52. Subspace theorems .....................................................................103. Addition and sum theorems..........................................................134. Cartesian product theorems.........................................................205. Compactification and completion theorems..................................246. Universal space theorems............................................................287....

Universal rational spaces

J. C. Mayer, E. D. Tymchatyn

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CONTENTS1. Introduction......................................................................52. Rim-type and decompositions..........................................83. Defining sequences and isomorphisms..........................184. Embedding theorem.......................................................265. Construction of universal and containing spaces...........326. References....................................................................39

Universal categories

Věra Trnková (1966)

Commentationes Mathematicae Universitatis Carolinae

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Polynomial approximations and universality

A. Mouze (2010)

Studia Mathematica

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We give another version of the recently developed abstract theory of universal series to exhibit a necessary and sufficient condition of polynomial approximation type for the existence of universal elements. This certainly covers the case of simultaneous approximation with a sequence of continuous linear mappings. In the case of a sequence of unbounded operators the same condition ensures existence and density of universal elements. Several known results, stronger statements or new results...