Induction proof.
We prove by induction that dag-omni-paths-round-p holds
for every round of the form
Theorem:
(defthm dag-omni-paths-round-p-of-round-delta (implies (and (certificate-setp dag1) (certificate-setp dag2) (certificate-set-unequivocalp dag1) (certificate-set-unequivocalp dag2) (certificate-sets-unequivocalp dag1 dag2) (dag-closedp dag1) (dag-closedp dag2) (dag-has-committees-p dag1 blockchain1) (dag-has-committees-p dag2 blockchain2) (dag-in-committees-p dag1 blockchain1) (dag-in-committees-p dag2 blockchain2) (same-active-committees-p blockchain1 blockchain2) (dag-predecessor-quorum-p dag2 blockchain2) (in cert dag1) (> (committee-members-stake (cert-set->author-set (successors cert dag1)) (active-committee-at-round (1+ (certificate->round cert)) blockchain1)) (committee-max-faulty-stake (active-committee-at-round (1+ (certificate->round cert)) blockchain1))) (natp round-delta)) (dag-omni-paths-round-p (+ round-delta (+ 2 (certificate->round cert))) cert dag2)))