Abstract
We prove a lower bound on the communication complexity of computing the n -fold xor of an arbitrary function f , in terms of the communication complexity and rank of f . We prove that D(f⊕n)≥n⋅(Ω(D(f))logrk(t)−logrk(f)) , where here D(f),D(f⊕n) represent the deterministic communication complexity, and rk(f) is the rank of f . Our methods involve a new way to use information theory to reason about deterministic communication complexity.