Superlogarithmic-Rank Matrix Rigidity for the Walsh-Hadamard Transform

Abstract

For sufficiently large $N$ which is a power of 2, we prove that changing at most one percent of the entries of the $N\times N$ Walsh-Hadamard Transform cannot reduce its rank over $\mathbb{F}_3$ to $\lfloor \log^2 N/80\rfloor$ or below. To the best of our knowledge, this is the first constant-fraction rigidity lower bound for an explicit matrix family at a superlogarithmic target rank over any choice of field, inching toward the parameters in Razborov's program for communication complexity lower bounds.