TFS system and selected papers

"The Typed Feature Structure Representation Formalism"

Abstract: The Typed Feature Structure (TFS) representation formalism defines the data model of the lexical knowledge base developed within the Delis project. The inheritance-based constraint architecture embodied in the TFS system integrates two computational paradigms: the object-oriented approach offers complex, recursive, possibly nested, record objects represented as typed feature structures with attribute-value restrictions and (in)equality constraints, and multiple inheritance; the relational programming approach offers declarativity, logical variables, non-determinism with backtracking, and existential query evaluation. The constraint-based properties of the TFS formalism are fully exploited in the Delis lexicon model and pertaining tools. These include corpus search and support for the major steps and types of activity in lexicon building: creation, population and modification of lexical models; exportation towards formats for both NLP and human use.

Martin C. Emele. "The Typed Feature Structure Representation Formalism". In Proceedings of the International Workshop on Sharable Natural Language Resources. August 10-11, 1994. Ikoma, Nara, Japan. Postscript

"Inheritance and Constraint-Based Grammar Formalisms"

Remi Zajac. "Inheritance and Constraint-Based Grammar Formalisms". In Computational Linguistics 18, pp. 159 - 180, 1992.

"Typed Unification Grammars"

Abstract: We introduce TFS, a computer formalism in the class of logic formalisms which integrates a powerful type system. Its basic data structures are typed feature structures. The type system encourages an object-oriented approach to linguisti c description by providing a multiple inheritance mechanism and an inference mechanism which allows the specification of relations between levels of linguist ic description defined as classes of objects. We illustrate this approach starting from a very simple DCG, and show how to make use of the typing system to enforce general constraints and modularize linguistic descriptions, and how further abstraction leads to a HPSG-like grammar.

Martin Emele and Remi Zajac. "Typed Unification Grammars". In Proceedings of the 13th International Workshop Conference on Computational Linguistics. August 1990. Helsinki. DVI File

"Unification with Lazy Non-Redundant Copying"

Abstract: This paper presents a unification procedure which eliminates the redundant copying of structures by using a lazy incremental copying approach to achieve structure sharing. Copying of structures accounts for a considerable amount of the total processing time. Several methods have been proposed to minimize the amount of necessary copying. Lazy Incremental Copying (LIC) is presented as a new solution to the copying problem. It synthesizes ideas of lazy copying with the notion of chronological dereferencing for achieving a high amount of structure sharing.

Martin C. Emele. "Unification with Lazy Non-Redundant Copying". In Proceedings of the 29th Annual Meeting of the Association for Computational Linguistics. June 1991. Berkeley. Pages 323-330. Postscript