Computing ideals of points

We address the problem of computing ideals of polynomials which vanish at a finite set of points. In particular we develop a modular Buchberger-Moller algorithm, best suited for the computation over Q, and study its complexit y; then we describe a variant for the computation of ideals of projective p oints, which uses a direct approach and a new stopping criterion. The descr ibed algorithms are implemented in CoCoA, and we report some experimental t imings. (C) 2000 Academic Press.