Paper: Estimation Of Consistent Probabilistic Context-Free Grammars

ACL ID N06-1044
Title Estimation Of Consistent Probabilistic Context-Free Grammars
Venue Human Language Technologies
Session Main Conference
Year 2006
Authors

We consider several empirical estimators for probabilistic context-free grammars, and show that the estimated grammars have the so-called consistency property, under the most general conditions. Our estimators include the widely applied ex- pectation maximization method, used to estimate probabilistic context-free gram- mars on the basis of unannotated corpora. This solves a problem left open in the lit- erature, since for this method the consis- tency property has been shown only under restrictive assumptions on the rules of the source grammar.