A sharp curvature lower bound for the first exterior p-harmonic Steklov eigenvalue

In this paper, we study the first variational Steklov eigenvalue of the $p$-Laplace equation on exterior domain ${\mathrm{\Omega }}^{\text{ext}}$ for $1<p<n$. If $\mathrm{\Omega }$ is convex and $\mathrm{\partial }\mathrm{\Omega }\in C^{1,1}$, we prove a sharp lower bound in terms of $p$-logarithmic mean of the principal curvatures of $\mathrm{\partial }\mathrm{\Omega }$. For the linear case $p=2$, our estimate reduces to the logarithmic mean bound of Bundrock et al. (arXiv:2511.09490). We also derive an upper bound in terms of a boundary isocapacitary constant. The analysis relies on the established finite energy theory on exterior domains, together with a decay estimate for $p$-harmonic extensions.