On the extremal solutions of superlinear Helmholtz problems

  • Makkia Dammak Taibah University Medinah
  • Majdi El Ghord University of Tunis El Manar
  • Saber Ali Kharrati Al Baha University

Abstract

Abstract: In this note, we deal with the Helmholtz equation −∆u+cu = λf(u) with Dirichlet boundary condition in a smooth bounded domain Ω of R n , n > 1. The nonlinearity is superlinear that is limt−→∞ f(t) t = ∞ and f is a positive, convexe and C 2 function defined on [0,∞). We establish existence of regular solutions for λ small enough and the bifurcation phenomena. We prove the existence of critical value λ ∗ such that the problem does not have solution for λ > λ∗ even in the weak sense. We also prove the existence of a type of stable solutions u ∗ called extremal solutions. We prove that for f(t) = e t , Ω = B1 and n ≤ 9, u ∗ is regular.

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Author Biography

Saber Ali Kharrati, Al Baha University

departement of mathamatic university of Manar 2 tunis-Tunisia

References

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Published
2021-12-16
Section
Articles