... visible.To adapt a PCFG to parse CW-grammars, weneed to define a PCF grammar for a given PCW- grammar by adding the two sets of rules while mak-ing sure that all meta -rules have been marked some-how. ... parsing algorithms.A probabilistic constrained W -grammar (PCW- grammar) consists of two different sets of PCF-like rules called pseudo -rules and meta -rules respec-tively and three pairwise disjoint ... Pseudo- rules and meta -rules provide mechanisms for build-ing ‘real’ rewrite rules. We use αw=⇒ β to indicatethat α should be rewritten as β. In the case of PCW-grammars, rewrite rules are...