DATR contains no special features to support testing of equality, negation, disjunction, or multiple inheritance. Nevertheless, given an appropriate interpretation it is possible, within DATR's existing syntax and semantics, to represent these operations. In this paper we review the technique known as negative path extension, and show how it can be used to reconstruct negation, disjunction, and equality testing. We then show how these operations can be used to define what are essentially meta-level constraints on DATR lexical derivation.
Download zip file