Restriction
In this lecture, we only consider the case of Chomsky Normal Form Grammars, which only have unary and binary rules of the form:
The parameters of a PCFG in Chomsky Normal Form are:
- P(Nj --> Nr Ns | G) , an n3 matrix of parameters
- P(Nj --> wk|G), nV parameters
(where n is the number of nonterminals and V is the number of terminals)
?r,s P(Nj --> Nr Ns) + ?k P (Nj --> wk) =1