But just as the Cocke-Kasami-Younger algorithm for context-free grammars can be thought of as a special case of intersecting a context-free language with a regular language (Bar-Hillel, Perles, and Shamir 1961), we would more generally like to be able to intersect [[G]] with any recognizable DAG language.
given an unweighted DAG automaton M, we would like to construct an HRG G such that [[G ] To discuss briefly how this can be done, we need to give a rough introduction to HRGs (adapted to the setting and terminology of the current article).