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Transactions of the American Mathematical Society

Published by the American Mathematical Society since 1900, Transactions of the American Mathematical Society is devoted to longer research articles in all areas of pure and applied mathematics.

ISSN 1088-6850 (online) ISSN 0002-9947 (print)

The 2020 MCQ for Transactions of the American Mathematical Society is 1.48.

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The distance function from the boundary in a Minkowski space
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by Graziano Crasta and Annalisa Malusa PDF
Trans. Amer. Math. Soc. 359 (2007), 5725-5759 Request permission

Abstract:

Let the space $\mathbb R^n$ be endowed with a Minkowski structure $M$ (that is, $M\colon \mathbb R^n \to [0,+\infty )$ is the gauge function of a compact convex set having the origin as an interior point, and with boundary of class $C^2$), and let $d^M(x,y)$ be the (asymmetric) distance associated to $M$. Given an open domain $\Omega \subset \mathbb R^n$ of class $C^2$, let $d_{\Omega }(x) := \inf \{d^M(x,y);\ y\in \partial \Omega \}$ be the Minkowski distance of a point $x\in \Omega$ from the boundary of $\Omega$. We prove that a suitable extension of $d_{\Omega }$ to $\mathbb R^n$ (which plays the rôle of a signed Minkowski distance to $\partial \Omega$) is of class $C^2$ in a tubular neighborhood of $\partial \Omega$, and that $d_{\Omega }$ is of class $C^2$ outside the cut locus of $\partial \Omega$ (that is, the closure of the set of points of nondifferentiability of $d_{\Omega }$ in $\Omega$). In addition, we prove that the cut locus of $\partial \Omega$ has Lebesgue measure zero, and that $\Omega$ can be decomposed, up to this set of vanishing measure, into geodesics starting from $\partial \Omega$ and going into $\Omega$ along the normal direction (with respect to the Minkowski distance). We compute explicitly the Jacobian determinant of the change of variables that associates to every point $x\in \Omega$ outside the cut locus the pair $(p(x), d_{\Omega }(x))$, where $p(x)$ denotes the (unique) projection of $x$ on $\partial \Omega$, and we apply these techniques to the analysis of PDEs of Monge–Kantorovich type arising from problems in optimal transportation theory and shape optimization.
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Additional Information
  • Graziano Crasta
  • Affiliation: Dipartimento di Matematica “G. Castelnuovo”, Univ. di Roma I, P.le A. Moro 2 – 00185 Roma, Italy
  • MR Author ID: 355300
  • ORCID: 0000-0003-3673-6549
  • Email: crasta@mat.uniroma1.it
  • Annalisa Malusa
  • Affiliation: Dipartimento di Matematica “G. Castelnuovo”, Univ. di Roma I, P.le A. Moro 2 – 00185 Roma, Italy
  • Email: malusa@mat.uniroma1.it
  • Received by editor(s): May 31, 2005
  • Published electronically: July 3, 2007
  • © Copyright 2007 American Mathematical Society
    The copyright for this article reverts to public domain 28 years after publication.
  • Journal: Trans. Amer. Math. Soc. 359 (2007), 5725-5759
  • MSC (2000): Primary 35A30; Secondary 26B05, 32F45, 35C05, 49L25, 58J60
  • DOI: https://doi.org/10.1090/S0002-9947-07-04260-2
  • MathSciNet review: 2336304