1,721,065 research outputs found

    Convex isoperimetric sets in the Heisenberg group

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    We characterize convex isoperimetric sets in the Heisenberg group. We first prove Sobolev regularity for a certain class of R2 -valued vector fields of bounded variation in the plane related to the curvature equations. Then we show that the boundary of convex isoperimetric sets is foliated by geodesics of the Carnot-Caratheodory distance

    Heisenberg isoperimetric problem. The axial case.

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    We prove Pansu’s conjecture about the Heisenberg isoperimetric problem in the class of axially symmetric sets. The result is based on a weighted rearrangement scheme in the half plane which is of independent interest

    Lipschitz approximation of H-perimeter minimizing boundaries

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    We prove that the boundary of H-perimeter minimizing sets in the Heisenberg group can be approximated by graphs that are intrinsic Lipschitz. The Hausdorff measure of the symmetric difference in a ball of graph and boundary is estimated by excess in a larger concentric ball. This result is motivated by a research program on the regularity of H-perimeter minimizing sets

    Rearrangements in metric spaces and in the Heisenberg group

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    We prove several rearrangement theorems in the setting of a metric measure space. We adapt the general scheme of the argument to the Heisenberg group, where we study Steiner and circular rearrangement for functions and sets having a suitable symmetry

    Sobolev inequalities for weighted gradients

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    We study symmetry, existence, and uniqueness properties of extremal functions for a weighted Sobolev inequalit

    Regularity results for sub-Riemannian geodesics

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    We study length minimality of abnormal curves in rank 2 sub-Rieman\-nian manifolds of polynomial type. As a corollary, we prove a C1,δC^{1,\delta} regularity result for Carnot-Carath\'eodory geode\-sics in a class of rank 2 Carnot groups

    Improved Lipschitz approximation of H-perimeter minimizing boundaries

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    We prove two new approximation results of H-perimeter minimizing boundaries by means of intrinsic Lipschitz functions in the setting of the Heisenberg group Hn with n≥2. The first one is an improvement of [19] and is the natural reformulation in Hn of the classical Lipschitz approximation in Rn. The second one is an adaptation of the approximation via maximal function developed by De Lellis and Spadaro [11]

    A family of nonminimizing abnormal curves

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    In a four dimensional sub-Riemannian structure, we study a specific family of abnormal extremals and we show that they are not length minimizing, answering in the negative to a question that was recently asked. We extend the result to a class of 4-dimensional sub-Riemannian manifolds of step 5
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