  The paper is concerned with Lane-Emden and Brezis-Nirenberg problems
involving the affine $p$-laplace nonlocal operator $\Delta_p^{\cal A}$, which
has been introduced in \cite{HJM5} driven by the affine $L^p$ energy ${\cal
E}_{p,\Omega}$ from convex geometry due to Lutwak, Yang and Zhang \cite{LYZ2}.
We are particularly interested in the existence and nonexistence of positive
$C^1$ solutions of least energy type. Part of the main difficulties are caused
by the absence of convexity of ${\cal E}_{p,\Omega}$ and by the comparison
${\cal E}_{p,\Omega}(u) \leq \Vert u \Vert_{W^{1,p}_0(\Omega)}$ generally
strict.
