Listar por autoría "c7af2c7f-57f1-4544-ba04-f5c282829fb8"
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A classification of the cofinal structures of precompacta
Elsevier (2020-08)We provide a complete classification of the possible cofinal structures of the families of precompact (totally bounded) sets in general metric spaces, and compact sets in general complete metric spaces. Using this ... -
A countable free closed non-reflexive subgroup of Zc
American Mathematical Society (2017)We prove that the group G = Hom(ZN, Z) of all homomorphisms from the Baer-Specker group ZN to the group Z of integer numbers endowed with the topology of pointwise convergence contains no infinite compact subsets. We ...
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A dichotomy property for locally compact groups
Elsevier (2018-08)We extend to metrizable locally compact groups Rosenthal's theorem describing those Banach spaces containing no copy of l1. For that purpose, we transfer to general locally compact groups the notion of interpolation (Io) ...
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Automatic continuity of biseparating homomorphisms defined between groups of continuous functions
Elsevier (2010)Let C(X,T{double-struck}) be the group of continuous functions of a compact Hausdorff space X to the unit circle of the complex plane T{double-struck} with the pointwise multiplication as the composition law. We investigate ... -
Balleans of topological groups
Springer Verlag (2011)A subset S of a topological group G is called bounded if, for every neighborhood U of the identity of G, there exists a finite subset F such that S ⊆ FU, S ⊆ UF. The family of all bounded subsets of G determines two ...
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Bounded Sets in Topological Spaces
MDPI (2022-02)Let G be a monoid that acts on a topological space X by homeomorphisms such that there is a point x0∈X with GU=X for each neighbourhood U of x0. A subset A of X is said to be G-bounded if for each neighbourhood U of x0 ...
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Cálculo
Universitat Jaume I (2009)
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Contributions to the Bohr topology by W.W. Comfort
Elsevier (2019)The important rôle that W. W. Comfort played in the study of the Bohr topology is described.
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Dual topologies on non-abelian groups
Elsevier (2012-06)The notion of locally quasi-convex abelian group, introduced by Vilenkin, is extended to maximally almost periodic non-necessarily abelian groups. For that purpose, we look at certain bornologies that can be defined on the ...
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Equicontinuity criteria for metric-valued sets of continuous functions
Elsevier (2017)Combining ideas of Troallic [1] and Cascales, Namioka, and Vera [2], we prove several characterizations of almost equicontinuity and hereditarily almost equicontinuity for subsets of metric-valued continuous functions ...
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Homomorphic encoders of profinite abelian groups I
Elsevier (2023-05)Let {Gi |i ∈ N} be a family of finite Abelian groups. We say that a subgroup G ≤ i∈N Gi is order controllable if for every i ∈ N there is ni ∈ N such that for each c ∈ G, there exists a ∈ G satisfying that a|[1,i] = ...
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Homomorphic Encoders of Profinite Abelian Groups II
MDPI (2022-03-29)Let {Gi:i∈N} be a family of finite Abelian groups. We say that a subgroup G≤∏i∈NGi is order controllable if for every i∈N, there is ni∈N such that for each c∈G, there exists c1∈G satisfying c1|[1,i]=c|[1,i], supp(c1)⊆[1,ni], ...
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Interpolation sets in spaces of continuous metric-valued functions
Elsevier (2018-10)Let X and K be a Cech-complete topological group and a compact group, ˇ respectively. We prove that if G is a non-equicontinuous subset of CHom(X; K), the set of all continuous homomorphisms of X into K, then there is a ...
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Nonmeasurable subgroups of compact groups
Walter de Gruyter GmbH (2015-10)In 1985 S. Saeki and K. Stromberg published the following question: Does every infinite compact group have a subgroup which is not Haar measurable? An affirmative answer is given for all compact groups with the exception ...
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On closed subgroups of precompact groups
De Gruyter (2022-09-28)It is a Theorem of W. W. Comfort and K. A. Ross that if G is a subgroup of a compact Abelian group, and S denotes those continuous homomorphisms from G to the one-dimensional torus, then the topology on G is the initial ...
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On convergent sequences in dual groups
Real Academia de Ciencias Exactas, Físicas y Naturales (2020-01-16)We provide some characterizations of precompact abelian groups G whose dual group G∧ p endowed with the pointwise convergence topology on elements of G contains a nontrivial convergent sequence. In the special case of ...
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Precompact groups and property (T)
Elsevier (2013-08)For a topological group GG, the dual object View the MathML sourceĜ is defined as the set of equivalence classes of irreducible unitary representations of GG equipped with the Fell topology. It is well known that, if GG ...
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Reflections in topological algebraic structures
Elsevier (2020-08)Let C be an epireflective subcategory of Top and let rC be the epireflective functor associated with C. If A denotes a (semi)topological algebraic subcategory of Top, we study when rC (A) is an epireflective subcategory ...
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Representation and approximation by series of continuous functions
Springer Verlag (2008)Let X be a topological space and let C (X) be the ring of all real-valued continuous functions defined on X. In this paper, we study the representation and approximation of continuous functions by sums of infinite series. ...
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Representation of group isomorphisms I
Elsevier (2019-08-15)Let G be a metric group and let Aut(G) denote the automorphism group of G. If A and B are groups of G-valued maps defined on the sets X and Y , respec- tively, we say that A and B are equivalent if there is a group ...
