910 research outputs found

    Equality in Borell-Brascamp-Lieb inequalities on curved spaces

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    By using optimal mass transportation and a quantitative H\"older inequality, we provide estimates for the Borell-Brascamp-Lieb deficit on complete Riemannian manifolds. Accordingly, equality cases in Borell-Brascamp-Lieb inequalities (including Brunn-Minkowski and Pr\'ekopa-Leindler inequalities) are characterized in terms of the optimal transport map between suitable marginal probability measures. These results provide several qualitative applications both in the flat and non-flat frameworks. In particular, by using Caffarelli's regularity result for the Monge-Amp\`ere equation, we {give a new proof} of Dubuc's characterization of the equality in Borell-Brascamp-Lieb inequalities in the Euclidean setting. When the nn-dimensional Riemannian manifold has Ricci curvature Ric(M)(n1)k{\rm Ric}(M)\geq (n-1)k for some kRk\in \mathbb R, it turns out that equality in the Borell-Brascamp-Lieb inequality is expected only when a particular region of the manifold between the marginal supports has constant sectional curvature kk. A precise characterization is provided for the equality in the Lott-Sturm-Villani-type distorted Brunn-Minkowski inequality on Riemannian manifolds. Related results for (not necessarily reversible) Finsler manifolds are also presented.Comment: 28 pages (with 1 figure); to appear in Advances in Mathematic

    Hausdorff dimension distribution of quasiconformal mappings on the Heisenberg group

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    We construct quasiconformal mappings on the Heisenberg group which change the Hausdorff dimension of Cantor-type sets in an arbitrary fashion. On the other hand, we give examples of subsets of the Heisenberg group whose Hausdorff dimension cannot be lowered by any quasiconformal mapping. For a general set of a certain Hausdorff dimension we obtain estimates of the Hausdorff dimension of the image set in terms of the magnitude of the quasiconformal distortio

    Weak contact equations for mappings into Heisenberg groups

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    Let k>n be positive integers. We consider mappings from a subset of k-dimensional Euclidean space R^k to the Heisenberg group H^n with a variety of metric properties, each of which imply that the mapping in question satisfies some weak form of the contact equation arising from the sub-Riemannian structure of the Heisenberg group. We illustrate a new geometric technique that shows directly how the weak contact equation greatly restricts the behavior of the mappings. In particular, we provide a new and elementary proof of the fact that the Heisenberg group H^n is purely k-unrectifiable. We also prove that for an open set U in R^k, the rank of the weak derivative of a weakly contact mapping in the Sobolev space W^{1,1}_{loc}(U;R^{2n+1}) is bounded by nn almost everywhere, answering a question of Magnani. Finally we prove that if a mapping from U to H^n is s-H\"older continuous, s>1/2, and locally Lipschitz when considered as a mapping into R^{2n+1}, then the mapping cannot be injective. This result is related to a conjecture of Gromov.Comment: 28 page

    Geometric inequalities on Heisenberg groups

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    We establish geometric inequalities in the sub-Riemannian setting of the Heisenberg group Hn\mathbb H^n. Our results include a natural sub-Riemannian version of the celebrated curvature-dimension condition of Lott-Villani and Sturm and also a geodesic version of the Borell-Brascamp-Lieb inequality akin to the one obtained by Cordero-Erausquin, McCann and Schmuckenschl\"ager. The latter statement implies sub-Riemannian versions of the geodesic Pr\'ekopa-Leindler and Brunn-Minkowski inequalities. The proofs are based on optimal mass transportation and Riemannian approximation of Hn\mathbb H^n developed by Ambrosio and Rigot. These results refute a general point of view, according to which no geometric inequalities can be derived by optimal mass transportation on singular spaces.Comment: to appear in Calculus of Variations and Partial Differential Equations (42 pages, 1 figure

    RELATIONSHIP BETWEEN ORGANIZATIONAL CULTURE AND CULTURAL INTELLIGENCE

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    This article examines one of the key competences of the 21st century, cultural intelligence. In our empirical research studies, we examined the cultural intelligence of full-time university students. We identified the corporate culture they would like to work in, and also examined if there is a correlation between their cultural intelligence and their preference for a particular corporate culture. We found that the majority of student would prefer to be employed in a Clan-type corporate culture. We also identified a correlation between their preferred corporate cultural and their cultural intelligence and its components. Students with a high degree of cultural intelligence would like to work in an adhocracy.Cameron and Quinn, CQS, cultural intelligence, Hungarian university student, OCAI, organizational culture.

    Quasiconformal mappings that highly distort dimensions of many parallel lines

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    We construct a quasiconformal mapping of nn-dimensional Euclidean space, n2n \geq 2, that simultaneously distorts the Hausdorff dimension of a nearly maximal collection of parallel lines by a given amount. This answers a question of Balogh, Monti, and Tyson.Comment: 12 page

    Rectifiability and Lipschitz extensions into the Heisenberg group

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    Denote by Hn{\mathbb{H}^n} the 2n+1 dimensional Heisenberg group. We show that the pairs (Rk,Hn){(\mathbb{R}^k ,\mathbb{H}^n)} and (Hk,Hn){(\mathbb{H}^k ,\mathbb{H}^n)} do not have the Lipschitz extension property for k >
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