Results 151 to 160 of about 92,595 (298)

Uniqueness of Positive Solutions of Semilinear Elliptic Equations

open access: yesJournal of Differential Equations, 1995
The uniqueness of positive solutions of the problem \[ \Delta u+ f(u)= 0, \quad u>0,\;x\in B_ R, \qquad u|_{\partial B_ R}=0, \] where \(f(u)\geq 0\), \(B_ R\) is a ball with radius \(R\) in \(\mathbb{R}^ n\), \(n>2\), is studied. The following nonlinearities \(f\) are considered: \(f(u)= u^ p+ u^ q\) and the more general case \(f(u)= \sum_{i=1}^ k a_ ...
openaire   +2 more sources

Inverse eigenvalue problems for semilinear elliptic equations

open access: yesElectronic Journal of Differential Equations, 2009
We consider the inverse nonlinear eigenvalue problem for the equation $$displaylines{ -Delta u + f(u) = lambda u, quad u > 0 quad hbox{in } Omega,cr u = 0 quad hbox{on } partialOmega, } where $f(u)$ is an unknown nonlinear term, $Omega subset ...
Tetsutaro Shibata
doaj  

Multiple solutions of nonlinear fractional elliptic equations via Morse theory

open access: yesElectronic Journal of Differential Equations, 2017
This article concerns the existence and multiplicity of weak solutions of the nonlinear fractional elliptic problem. We extend some well known results of semilinear Laplacian equations to the nonlocal fractional setting. Using the variational methods
Wei Qi, Lin Zhao, Xingjie Yan
doaj  

A free boundary problem for semilinear elliptic equations

open access: yes, 1986
The regularity of the free boundary for the following problem was investigated: \[ \Delta u=a(x,u)\gamma u^{\gamma -1}\text{ on } \Omega \cap \{u>0\},\quad 00\}\) where a tangent plane in measure exists, which is denoted by \(\partial_{red}\{u>0\};\) 3) A notion of 'flat' free boundary point was introduced; 4) The \(C^{1,\alpha}\) surface regularity of
Alt, H.W., Phillips, D.
openaire   +1 more source

Elastic anisotropy in the reduced Landau-de Gennes model. [PDF]

open access: yesProc Math Phys Eng Sci, 2022
Han Y, Harris J, Majumdar A, Zhang L.
europepmc   +1 more source

An inverse boundary-value problem for semilinear elliptic equations

open access: yesElectronic Journal of Differential Equations, 2010
We show that in dimension two or greater, a certain equivalence class of the scalar coefficient $a(x,u)$ of the semilinear elliptic equation $Delta u,+a(x,u)=0$ is uniquely determined by the Dirichlet to Neumann map of the equation on a bounded ...
Ziqi Sun
doaj  

Multiplicity results for nonlinear elliptic equations

open access: yesElectronic Journal of Differential Equations, 2006
Let $Omega$ be a bounded domain in $mathbb{R}^{N}$, $Ngeq 3$, and $p=frac{2N}{N-2}$ the limiting Sobolev exponent. We show that for $fin H^1_0(Omega)^ast$, satisfying suitable conditions, the nonlinear elliptic problem $$displaylines{ -Delta u =|u |^{ p ...
Samira Benmouloud   +2 more
doaj  

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