Polynomial interpolation and residue currents

Abstract

We show that a global holomorphic section of $\mathscr{O}(d)$ restricted to a closed complex subspace $X \subset \mathbb{P}^n$ has an interpolant if and only if it satisfies a set of moment conditions that involves a residue current associated with a locally free resolution of $\mathscr{O}_X$. When $X$ is a finite set of points in $\mathbb{C}^n \subset \mathbb{P}^n$ this can be interpreted as a set of linear conditions that a function on $X$ has to satisfy in order to have a polynomial interpolant of degree at most $d$.