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Uniformly completely Ramsey sets

Udayan Darji (1993)

Colloquium Mathematicae

Galvin and Prikry defined completely Ramsey sets and showed that the class of completely Ramsey sets forms a σ-algebra containing open sets. However, they used two definitions of completely Ramsey. We show that they are not equivalent as they remarked. One of these definitions is a more uniform property than the other. We call it the uniformly completely Ramsey property. We show that some of the results of Ellentuck, Silver, Brown and Aniszczyk concerning completely Ramsey sets also hold for uniformly...

Uniformly countably additive families of measures and group invariant measures.

Baltasar Rodríguez-Salinas (1998)

Collectanea Mathematica

The extension of finitely additive measures that are invariant under a group permutations or mappings has already been widely studied. We have dealt with this problem previously from the point of view of Hahn-Banach's theorem and von Neumann's measurable groups theory. In this paper we construct countably additive measures from a close point of view, different to that of Haar's Measure Theory.

Unimodular Pisot substitutions and their associated tiles

Jörg M. Thuswaldner (2006)

Journal de Théorie des Nombres de Bordeaux

Let σ be a unimodular Pisot substitution over a d letter alphabet and let X 1 , ... , X d be the associated Rauzy fractals. In the present paper we want to investigate the boundaries X i ( 1 i d ) of these fractals. To this matter we define a certain graph, the so-called contact graph 𝒞 of σ . If σ satisfies a combinatorial condition called the super coincidence condition the contact graph can be used to set up a self-affine graph directed system whose attractors are certain pieces of the boundaries X 1 , ... , X d . From this graph...

Unions et intersections d’espaces L p invariantes par translation ou convolution

Jean-Paul Bertrandias, Christian Datry, Christian Dupuis (1978)

Annales de l'institut Fourier

Étude des propriétés des unions et intersections d’espaces L p ( s ) relatifs à un ensemble S de mesures positives sur un groupe commutatif localement compact lorsque S est invariant par translation ou stable par convolution.Dans des cas particuliers, on retrouve les propriétés d’espaces étudiés par A. Beurling et par B. Koremblium.On étudie aussi les espaces p ( L p ' ) formés des fonctions appartenant localement à L p ' et qui ont un comportement p à l’infini.

Unique Bernoulli g -measures

Anders Johansson, Anders Öberg, Mark Pollicott (2012)

Journal of the European Mathematical Society

We improve and subsume the conditions of Johansson and Öberg and Berbee for uniqueness of a g -measure, i.e., a stationary distribution for chains with complete connections. In addition, we prove that these unique g -measures have Bernoulli natural extensions. We also conclude that we have convergence in the Wasserstein metric of the iterates of the adjoint transfer operator to the g -measure.

Uniqueness and approximate computation of optimal incomplete transportation plans

P. C. Álvarez-Esteban, E. del Barrio, J. A. Cuesta-Albertos, C. Matrán (2011)

Annales de l'I.H.P. Probabilités et statistiques

For α∈(0, 1) an α-trimming, P∗, of a probability P is a new probability obtained by re-weighting the probability of any Borel set, B, according to a positive weight function, f≤1/(1−α), in the way P∗(B)=∫Bf(x)P(dx). If P, Q are probability measures on euclidean space, we consider the problem of obtaining the best L2-Wasserstein approximation between: (a) a fixed probability and trimmed versions of the other; (b) trimmed versions of both probabilities. These best trimmed approximations naturally...

Uniqueness of a martingale-coboundary decomposition of stationary processes

Pavel Samek, Dalibor Volný (1992)

Commentationes Mathematicae Universitatis Carolinae

In the limit theory for strictly stationary processes f T i , i , the decomposition f = m + g - g T proved to be very useful; here T is a bimeasurable and measure preserving transformation an ( m T i ) is a martingale difference sequence. We shall study the uniqueness of the decomposition when the filtration of ( m T i ) is fixed. The case when the filtration varies is solved in [13]. The necessary and sufficient condition of the existence of the decomposition were given in [12] (for earlier and weaker versions of the results see [7])....

Uniqueness of Brownian motion on Sierpiński carpets

Martin Barlow, Richard F. Bass, Takashi Kumagai, Alexander Teplyaev (2010)

Journal of the European Mathematical Society

We prove that, up to scalar multiples, there exists only one local regular Dirichlet form on a generalized Sierpi´nski carpet that is invariant with respect to the local symmetries of the carpet. Consequently, for each such fractal the law of Brownian motion is uniquely determined and the Laplacian is well defined.

Uniqueness of measure extensions in Banach spaces

J. Rodríguez, G. Vera (2006)

Studia Mathematica

Let X be a Banach space, B B X * a norming set and (X,B) the topology on X of pointwise convergence on B. We study the following question: given two (non-negative, countably additive and finite) measures μ₁ and μ₂ on Baire(X,w) which coincide on Baire(X,(X,B)), does it follow that μ₁ = μ₂? It turns out that this is not true in general, although the answer is affirmative provided that both μ₁ and μ₂ are convexly τ-additive (e.g. when X has the Pettis Integral Property). For a Banach space Y not containing...

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