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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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Dirichlet regularity and degenerate diffusion
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by Wolfgang Arendt and Michal Chovanec PDF
Trans. Amer. Math. Soc. 362 (2010), 5861-5878 Request permission

Abstract:

Let $\Omega \subset \mathbb {R}^N$ be an open and bounded set and let $m\colon \Omega \rightarrow (0,\infty )$ be measurable and locally bounded. We study a natural realization of the operator $m \triangle$ in $C_0(\Omega ):=\left \lbrace u\in C(\overline {\Omega }):\;u_{\vert \partial \Omega }=0\right \rbrace$. If $\Omega$ is Dirichlet regular, then the operator generates a positive contraction semigroup on $C_0(\Omega )$ whenever $\frac {1}{m}\in L^p_{\operatorname {loc}}(\Omega )$ for some $p>\frac {N}{2}$. If $m(x)$ does not go fast enough to $0$ as $x\rightarrow \partial \Omega$, then Dirichlet regularity is necessary. However, if $\vert m(x)\vert \leq c\cdot \operatorname {dist}(x,\partial \Omega )^2$, then we show that $m \triangle _0$ generates a semigroup on $C_0(\Omega )$ without any regularity assumptions on $\Omega$. We show that the condition for degeneration of $m$ near the boundary is optimal.
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Additional Information
  • Wolfgang Arendt
  • Affiliation: Institute of Applied Analysis, University of Ulm, 89069 Ulm, Germany
  • MR Author ID: 26945
  • Email: wolfgang.arendt@uni-ulm.de
  • Michal Chovanec
  • Affiliation: Institute of Applied Analysis, University of Ulm, 89069 Ulm, Germany
  • Email: michal.chovanec@uni-ulm.de
  • Received by editor(s): July 21, 2008
  • Published electronically: June 10, 2010
  • © Copyright 2010 American Mathematical Society
    The copyright for this article reverts to public domain 28 years after publication.
  • Journal: Trans. Amer. Math. Soc. 362 (2010), 5861-5878
  • MSC (2010): Primary 35K05, 47D06
  • DOI: https://doi.org/10.1090/S0002-9947-2010-05077-9
  • MathSciNet review: 2661499