3 problems

Let $I=[a,b]$ and let $\mathbf{x}$ be a node system, with interval maxima … where $I_i(\mathbf{x})=[x_{i-1},x_i]$ for $1\leq i\leq n$ and $I_{n+1}(\mathbf{x})=[x_n,\infty)$. Bernst…

Let $I=[a,b]$ and let $\mathbf{x}$ be an optimal, equioscillating node system for weighted Lagrange interpolation, so that … For any other node system $\mathbf{y}$, let…

Calvi–Phung's conjecture. For every $N\geq1$,