Capturing Disjunction In Lexicalization With Extensible Dependency Grammar

In spite of its potential for bidirectionality, Extensible Dependency Grammar (XDG) has so far been used almost exclusively for parsing. This paper represents one of the first steps towards an XDG-based integrated generation architecture by tackling what is arguably the most basic among generation tasks: lexicalization. Herein we present a constraint-based account of disjunction in lexicalization, i.e. a way to enable an XDG grammar to generate all paraphrases — along the lexicalization axis, of course — realizing a given input semantics. Our model is (i) efficient, yielding strong propagation, (ii) modular and (iii) favourable to synergy inasmuch as it allows collaboration between modules, notably semantics and syntax. We focus on constraints ensuring wellformedness and completeness and avoiding over-redundancy.