A finite-order characterization of entrywise positivity preservers

Ludovick Bouthat, Dominique Guillot

Let $I=(0,\rho )$, where $0<\rho \le \infty$, and let ${\mathbb{P}}_n(I)$ denote the cone of real positive semidefinite $n\times n$ matrices whose entries belong to $I$. A longstanding probl…