Language:   Search:   Contact
Zentralblatt MATH has released its new interface!
For an improved author identification, see the new author database of ZBMATH.

Query:
Fill in the form and click »Search«...
Format:
Display: entries per page entries
Zbl 0844.35035
Marino, A.; Micheletti, A.M.; Pistoia, A.
A nonsymmetric asymptotically linear elliptic problem.
(English)
[J] Topol. Methods Nonlinear Anal. 4, No.2, 289-339 (1994). ISSN 1230-3429

Let $\Omega$ be a bounded domain in $\bbfR^N$. The paper is concerned with the semilinear elliptic problem $$\Delta u+ g(x, u)= te_1 \quad \text{in }\Omega, \qquad u= 0 \quad \text{on }\partial\Omega,\tag *$$ where $g(x, u)= \alpha u^++ \beta u^-+ g_0(x, u)$, $g_0(x, u)/u\to 0$ as $|u|\to \infty$, $e_1$ is the positive eigenvalue of the Laplacian and $\alpha, \beta, t\in \bbfR$. To $(*)$ there corresponds a functional $$f_t(u)= \int_\Omega (\textstyle{{1\over 2}} |\nabla u|^2- G(x, u)+ te_1 u)dx$$ in $H^1_0(\Omega)$ and critical points of $f_t$ are solutions of $(*)$. It is shown that for $(\alpha, \beta)$ in certain regions of $\bbfR^2$, if $t$ is large enough, then $(*)$ has at least one, two, three, respectively four solutions. Existence of one solution is shown by using a variant of the saddle point theorem of Rabinowitz. Two and three solutions are obtained by linking-type arguments where careful estimates are needed in order to show that certain linking levels are different. An additional argument gives a fourth critical point. It should also be noted that a rather general sufficient condition for $f_t$ to satisfy the Palais-Smale condition is given in this paper.
[A.Szulkin (Stockholm)]
MSC 2000:
*35J65 (Nonlinear) BVP for (non)linear elliptic equations
58E05 Abstract critical point theory
35J20 Second order elliptic equations, variational methods

Keywords: jumping nonlinearity; semilinear elliptic equation; linking; multiple solutions

Highlights
Master Server