2 problems

Matheron's characterization conjecture. Matheron's inequalities are not only necessary but also sufficient to characterize a first-order stationary indicator variogram.

Let $K=\\{\bm{x}_i\\}_{i=1,\dots,N}$ be a finite set of distinct points in $\mathbb{R}^d$ with at least two elements. Define … where $\alpha\in(0,1]$, and let…