Largest zero-dimensional intersection of $r$ degree $d$ hypersurfaces

Abstract

Suppose we have $r$ hypersurfaces in ${\mathbb{P}}^m$ of degree $d$, whose defining polynomials are linearly independent, and their intersection has dimension $0$. Then what is the largest possible intersection of the $r$ hypersurfaces? We conjecture an exact formula for this problem and prove it when $m=2$. We show that this can be used to compute the generalized hamming weights of the projective Reed-Muller code ${\mathrm{PRM}}_q(d,2)$ and hence settle a conjecture of Beelen, Datta and Ghorpade for $m=2$.