2 problems

A Fenn graph is the graph $G(f)$ of a continuous map $f:\mathbb{R}^{2}\to\mathbb{R}$ over a compact convex domain $D\subset\mathbb{R}^{2}$ satisfying Fenn's boundary conditions. Le…

A saddle surface is the graph $G(f)$ of a continuous map $f:\mathbb{R}^{2}\to\mathbb{R}$ satisfying the saddle-surface conditions, with center at the origin. Let…