Parse Selection Computing most likely unsplit tree is NP-hard: Settle for best derivation. Rerank n-best list. Use alternative objective function. Parses: -2 Derivations:
Parse Risk Minimization Expected loss according to our beliefs: T T : true tree T P : predicted tree L : loss function (0/1, precision, recall, F1) [Titov & Henderson ‘06] Use n-best candidate list and approximate expectation with samples.