CS 369 E : Communication Complexity ( for Algorithm Designers ) Lecture # 2 : Lower Bounds for One-Way Communication : Disjointness , Index , and Gap-Hamming ∗

Recall from last lecture the simple but useful model of one-way communication complexity. Alice has an input x ∈ {0, 1}, Bob has an input y ∈ {0, 1}, and the goal is to compute a Boolean function f : {0, 1} × {0, 1} → {0, 1} of the joint input (x,y). The players communicate as in Figure ??: Alice sends a message z to Bob as a function of x only (she doesn’t… CONTINUE READING