Report Number: CS-TR-68-103
Institution: Stanford University, Department of Computer Science
Title: Lexical insertion in transformational grammar
Author: Friedman, Joyce
Author: Bredt, Thomas H.
Date: June 1968
Abstract: In this paper, we describe the lexical insertion process for generative transformational grammars. We also give detailed descriptions of many of the concepts in transformational theory. These include the notions of complex symbol, syntactic feature (particularly contextual feature), redundancy rule, tests for pairs of complex symbols, and change operations that may be applied to complex symbols. Because of our general interpretation of redundancy rules, we define a new complex symbol test known as compatibility. This test replaces the old notion of nondistinctness. The form of a lexicon suitable for use with a generative grammar is specified. In lexical insertion, vocabulary words and associated complex symbols are selected from a lexicon and inserted at lexical category nodes in the tree. Complex symbols are lists of syntactic features. The compatibility of a pair of complex symbols and the analysis procedure used for contextual features are basic in determining suitable items for insertion. Contextual features (subcategorization and selectional) have much in common with the structural description for a transformation and we use the same analysis procedure for both. A problem encountered in the insertion of a complex symbol that contains selectional features is side effects. We define the notion of side effects and describe how these effects are to be treated. The development of the structure of the lexicon and the lexical insertion algorithm has been aided by a system of computer programs that enable the linguist to study transformational grammar. In the course of this development, a computer program to perform lexical insertion was written. Results obtained using this program with fragments of transformational grammar are presented. The paper concludes with suggestions for extensions of this work and a discussion of interpretations of transformational theory that do not fit immediately into our framework.