Chalk Talk
Lemma 𝛿(s, v) ≤ 𝛿(s, u) + 1 for all (u,v) in E.
Proof Idea
Lemma d[v] ≥ 𝛿(s, v) for all v in V, at any point during BFS
Proof Idea
Lemma if Q = [v1, … vr], then d[vi] ≤ d[vi+1] for each i and
d[vr] ≤ d[v1] + 1
Proof Idea