pub trait NoValidatedBlockInFastRound: NoValidationInFastRound + CertificateCarriesCorrectVote { }Expand description
Lemma (No validated block certificate in the fast round). No valid
ValidatedBlockCertificate is certified in
Round::Fast.
Proof. By CertificateCarriesCorrectVote such a certificate would require a correct
validator to have cast a validation vote in Round::Fast,
which NoValidationInFastRound forbids. ∎
This is why the fast round is not a “round” in the ordinary sense: it has a confirmation step but no validation step, and therefore no certificate a later round could be unlocked by.