Ground state solutions for a semilinear elliptic problem with critical-subcritical growth

In this work, we study the of positive ground state solution for the semilinear elliptic problem \left\{ \begin{array} [c]{ll}% -\Delta u=u^{p(x)-1},\quad u>0 & \mathrm{in}\,G\subseteq\mathbb{R}^{N}% ,\,N\geq3\\ u\in D_{0}^{1,2}(G), & \end{array} \right. where $G$ is either ${\mathbb{R}}^N$ or a bounded domain, and $p:G\to \mathbb{R}$ is a continuous function assuming critical and subcritical values.