Paper: Conditions on Consistency of Probabilistic Tree Adjoining Grammars

ACL ID P98-2190
Title Conditions on Consistency of Probabilistic Tree Adjoining Grammars
Venue Annual Meeting of the Association of Computational Linguistics
Session Main Conference
Year 1998
Authors
  • Anoop Sarkar (University of Pennsylvania, Philadelphia PA)

Much of the power of probabilistic methods in modelling language comes from their ability to compare several derivations for the same string in the language. An important starting point for the study of such cross-derivational proper- ties is the notion of consistency. The probabil- ity model defined by a probabilistic grammar is said to be consistent if the probabilities assigned to all the strings in the language sum to one. From the literature on probabilistic context-free grammars (CFGs), we know precisely the con- ditions which ensure that consistency is true for a given CFG. This paper derives the conditions under which a given probabilistic Tree Adjoin- ing Grammar (TAG) can be shown to be con- sistent. It gives a simple algorithm for checking consistency and gives the formal justif...