Nabla

More than three decades ago Richard Montague presented a formal description of the syntax and semantics of a fragment of English that included verbs, nouns, negation, coordination and quantification as well as propositional attitudes like assertion, knowledge and belief. Nabla improves the syntactical part of this approach by following modern lexicalist trends and, most importantly, enriches the type system underlying the semantics by several innovations. By this it meets the current on-going debate about extensions of type theory recently discussed in computer science, logic and linguistics.