Revista Integración, temas de matemáticas.
Vol. 28 No. 2 (2010): Revista Integración, temas de matemáticas
Research and Innovation Articles

Remarks on positive and free boundary solutions to a singular equation

Juan Dávila
Universidad de Chile
Marcelo Montenegro
Universidade Estadual de Campinas

Published 2010-09-21

Keywords

  • Singular equations,
  • free boundary

How to Cite

Dávila, J., & Montenegro, M. (2010). Remarks on positive and free boundary solutions to a singular equation. Revista Integración, Temas De matemáticas, 28(2), 85–100. Retrieved from https://revistas.uis.edu.co/index.php/revistaintegracion/article/view/2169

Abstract

The equation −∆u = χ{u>0} (− 1/(u^β) + λf(x, u) in Ω with Dirichlet boundary condition on ∂Ω has a maximal solution uλ ≥ 0 for every λ > 0. For λ less than a constant λ ∗ the solution vanishes inside the domain, and for λ > λ∗ the solution is positive and stable. We obtain optimal regularity of uλ even in the presence of the free boundary. If 0 < λ < λ∗ the solutions of the singular parabolic equation ut − ∆u + 1/(u^β) = λf(u) quench in finite time, and for λ > λ∗ the solutions are globally positively defined.

 

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