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A Q -linear automorphism of the reals with non-measurable graph

Stephen Scheinberg (2019)

Commentationes Mathematicae Universitatis Carolinae

This note contains a proof of the existence of a one-to-one function Θ of onto itself with the following properties: Θ is a rational-linear automorphism of , and the graph of Θ is a non-measurable subset of the plane.

A quantitative version of the isoperimetric inequality : the anisotropic case

Luca Esposito, Nicola Fusco, Cristina Trombetti (2005)

Annali della Scuola Normale Superiore di Pisa - Classe di Scienze

We state and prove a stability result for the anisotropic version of the isoperimetric inequality. Namely if E is a set with small anisotropic isoperimetric deficit, then E is “close” to the Wulff shape set.

A remark on a theorem of Solecki

Petr Holický, Luděk Zajíček, Miroslav Zelený (2005)

Commentationes Mathematicae Universitatis Carolinae

S. Solecki proved that if is a system of closed subsets of a complete separable metric space X , then each Suslin set S X which cannot be covered by countably many members of contains a G δ set which cannot be covered by countably many members of . We show that the assumption of separability of X cannot be removed from this theorem. On the other hand it can be removed under an extra assumption that the σ -ideal generated by is locally determined. Using Solecki’s arguments, our result can be used...

A Riemann approach to random variation

Patrick Muldowney (2006)

Mathematica Bohemica

This essay outlines a generalized Riemann approach to the analysis of random variation and illustrates it by a construction of Brownian motion in a new and simple manner.

A Riesz representation theory for completely regular Hausdorff spaces and its applications

Marian Nowak (2016)

Open Mathematics

Let X be a completely regular Hausdorff space, E and F be Banach spaces. Let Cb(X, E) be the space of all E-valued bounded, continuous functions on X, equipped with the strict topology β. We develop the Riemman-Stieltjes-type Integral representation theory of (β, || · ||F) -continuous operators T : Cb(X, E) → F with respect to the representing Borel operator measures. For X being a k-space, we characterize strongly bounded (β, || · ||F)-continuous operators T : Cb(X, E) → F. As an application, we...

A rough curvature-dimension condition for metric measure spaces

Anca-Iuliana Bonciocat (2014)

Open Mathematics

We introduce and study a rough (approximate) curvature-dimension condition for metric measure spaces, applicable especially in the framework of discrete spaces and graphs. This condition extends the one introduced by Karl-Theodor Sturm, in his 2006 article On the geometry of metric measure spaces II, to a larger class of (possibly non-geodesic) metric measure spaces. The rough curvature-dimension condition is stable under an appropriate notion of convergence, and stable under discretizations as...

A saddle-point approach to the Monge-Kantorovich optimal transport problem

Christian Léonard (2011)

ESAIM: Control, Optimisation and Calculus of Variations

The Monge-Kantorovich problem is revisited by means of a variant of the saddle-point method without appealing to c-conjugates. A new abstract characterization of the optimal plans is obtained in the case where the cost function takes infinite values. It leads us to new explicit sufficient and necessary optimality conditions. As by-products, we obtain a new proof of the well-known Kantorovich dual equality and an improvement of the convergence of the minimizing sequences.

A saddle-point approach to the Monge-Kantorovich optimal transport problem

Christian Léonard (2011)

ESAIM: Control, Optimisation and Calculus of Variations

The Monge-Kantorovich problem is revisited by means of a variant of the saddle-point method without appealing to c-conjugates. A new abstract characterization of the optimal plans is obtained in the case where the cost function takes infinite values. It leads us to new explicit sufficient and necessary optimality conditions. As by-products, we obtain a new proof of the well-known Kantorovich dual equality and an improvement of the convergence of the minimizing sequences.

A Sard type theorem for Borel mappings

Piotr Hajłasz (1994)

Colloquium Mathematicae

We find a condition for a Borel mapping f : m n which implies that the Hausdorff dimension of f - 1 ( y ) is less than or equal to m-n for almost all y n .

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