Hybrid Grammars for Discontinuous Parsing
Mark-Jan Nederhof, Heiko Vogler · International Conference on Computational Linguistics · 2014
We introduce the concept of hybrid grammars, which are extensions of synchronous grammars, obtained by coupling of lexical elements. One part of a hybrid grammar generates linear structures, another generates hierarchical structures, and together they generate discontinuous structures. This formalizes and generalizes some existing mechanisms for dealing with discontinuous phrase structures and non-projective dependency structures. Moreover, it allows us to separate the degree of discontinuity from the time complexity of parsing.