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Volume distribution and the geometry of high-dimensional random polytopes

  • Author / Creator
    Pivovarov, Peter
  • This thesis is based on three papers on selected topics in
    Asymptotic Geometric Analysis.

    The first paper is about the volume of high-dimensional random
    polytopes; in particular, on polytopes generated by Gaussian random
    vectors. We consider the question of how many random vertices (or
    facets) should be sampled in order for such a polytope to capture
    significant volume. Various criteria for what exactly it means to
    capture significant volume are discussed. We also study similar
    problems for random polytopes generated by points on the Euclidean
    sphere.

    The second paper is about volume distribution in convex bodies. The
    first main result is about convex bodies that are (i) symmetric with
    respect to each of the coordinate hyperplanes and (ii) in isotropic
    position. We prove that most linear functionals acting on such
    bodies exhibit super-Gaussian tail-decay. Using known facts about
    the mean-width of such bodies, we then deduce strong lower bounds
    for the volume of certain caps. We also prove a converse statement.
    Namely, if an arbitrary isotropic convex body (not necessarily
    satisfying the symmetry assumption (i)) exhibits similar
    cap-behavior, then one can bound its mean-width.

    The third paper is about random polytopes generated by sampling
    points according to multiple log-concave probability measures. We
    prove related estimates for random determinants and give
    applications to several geometric inequalities; these include
    estimates on the volume-radius of random zonotopes and Hadamard's
    inequality for random matrices.

  • Subjects / Keywords
  • Graduation date
    Fall 2010
  • Type of Item
    Thesis
  • Degree
    Doctor of Philosophy
  • DOI
    https://doi.org/10.7939/R36C8J
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.
  • Language
    English
  • Institution
    University of Alberta
  • Degree level
    Doctoral
  • Department
  • Supervisor / co-supervisor and their department(s)
  • Examining committee members and their departments
    • Litvak, Alexander (Mathematical and Statistical Sciences)
    • Yaskin, Vlad (Mathematical and Statistical Sciences)
    • Werner, Elisabeth (Mathematics, Case Western Reserve University)
    • Lau, Anthony To-Ming (Mathematical and Statistical Sciences)
    • Troitsky, Vladimir (Mathematical and Statistical Sciences)
    • Stewart, Lorna (Computing Sciences)