## Decaying solutions of semilinear elliptic equations in $$R^ N$$.(English)Zbl 0696.35051

The authors study existence and asymptotic behavior of positive classical solutions of the semilinear elliptic equation $$-\Delta u+bu=\lambda pf(u)$$ in $${\mathbb{R}}^ N$$, $$N\geq 2$$, where b and p are radially symmetric, bounded and locally Hölder continuous functions in $${\mathbb{R}}^ N$$, $$b\geq 0$$, $$p>0$$, f: $${\mathbb{R}}^+\to {\mathbb{R}}$$ is locally Lipschitz continuous, $$f(t)>0$$ iff $$0<t<T$$, $$f(t)=O(t^{\gamma})$$ as $$t\downarrow 0$$, $$\gamma >1$$, and the solutions are sought in the class of functions which decay uniformly to zero at $$\infty$$. The existence of a solution pair $$(\lambda,u_{\lambda})$$ and an asymptotic estimate for $$u_{\lambda}$$ is proved by a direct variational approach if $$b(r)\geq b_ 0>0$$, and by an approximation procedure (in which the function b(r) is approximated by $$b(r)+1/k)$$ if b(r)$$\geq 0$$. The more important latter case is proved under the additional hypothesis $$N\geq 3$$ and $$p(r)=O(r^{-a})$$ as $$r\to \infty$$, where $$\gamma >(N-2a+2)/(N-2)$$.
Reviewer: P.Quittner

### MSC:

 35J65 Nonlinear boundary value problems for linear elliptic equations 35P30 Nonlinear eigenvalue problems and nonlinear spectral theory for PDEs 35B40 Asymptotic behavior of solutions to PDEs 35J20 Variational methods for second-order elliptic equations
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