  Let $\Omega$ be a bounded, smooth domain of $\mathbb{R}^{N},$ $N\geq2.$ For
$p>N$ and $1\leq q(p)<\infty$ set \[ \lambda_{p,q(p)}:=\inf\left\{
\int_{\Omega}\left\vert \nabla u\right\vert ^{p}\mathrm{d}x:u\in
W_{0}^{1,p}(\Omega)\text{ \ and \ }\int_{\Omega }\left\vert u\right\vert
^{q(p)}\mathrm{d}x=1\right\} \] and let $u_{p,q(p)}$ denote a corresponding
positive extremal function. We show that if
$\lim\limits_{p\rightarrow\infty}q(p)=\infty$, then
$\lim\limits_{p\rightarrow\infty}\lambda_{p,q(p)}^{1/p}=\left\Vert d_{\Omega
}\right\Vert _{\infty}^{-1}$, where $d_{\Omega}$ denotes the distance function
to the boundary of $\Omega.$ Moreover, in the hyperdiffusive case:
$\lim\limits_{p\rightarrow\infty}\frac{q(p)}{p}=\infty,$ we prove that each
sequence $u_{p_{n},q(p_{n})},$ with $p_{n}\rightarrow\infty,$ admits a
subsequence converging uniformly in $\overline{\Omega}$ to a viscosity solution
to the problem \[ \left\{ \begin{array} [c]{lll} -\Delta_{\infty}u=0 &
\text{in} & \Omega\setminus M\\ u=0 & \text{on} & \partial\Omega\\ u=1 &
\text{in} & M, \end{array} \right. \] where $M$ is a closed subset of the set
of all maximum points of $d_{\Omega}.$
