Abstract:
It is proved that the problem
$$
\sum_{i=1}^N\nabla_i(|\nabla u|^{p-2}\nabla_iu)+|u|^{p^*-2}u+\lambda|u|^{q-2}u=0 \text{ in } \Omega, \quad u=0 \text{ on } \partial\Omega,
$$
where $\Omega\subset\mathbf{R}^N$ a singly-connected region with an “odd” boundary, $N>p$, and $p^*=Np/(N-p)$ is a critical Sobolev exponent, has, under the appropriate conditions on $\lambda$, $q$ and $N$, no less than $(2N+2)$ nontrivial solutions in $\mathring{W}_{p^1}(\Omega)$.