An Algebra for Semantic Construction in Constraint-based Grammars

Every language employs its own coordination strategies, according to the type of coordinating marking, the pattern of marking, the position of the marker, and the phrase types coordinated. The SOV language Korean is intriguing in the sense that it displays almost all the possibilities of these dimensions. This paper shows how a typed feature structure grammar, HPSG, together with the notions of 'type hierarchy' and 'constructions', can provide a robust basis for parsing the coordination constructions found in the language. We show that this system induces robust syntactic structures as well as enriched semantic representations for real-time applications such as machine translation, which require deep processing of the phenomena concerned.

this paper is, therefore, to re-represent systemic grammar resources in a standard typed feature logic in order (1) to clarify theoretically the relation between systemic grammar and state-of-the-art feature logics, and (2) to serve as point of departure for bidirectional processing of systemic grammar. Four such representations in the feature logic formalisms ale, tfs, cuf and tdl

1989

This paper shows how higher levels of generalization can be introduced into unification grammars by exploiting methods for typing grammatical objects. We discuss the strategy of using global declarations to limit possible linguistic structures, and sketch a few unusual aspects of our typechecking algorithm. We also describe the sort system we use in our semantic representation language and illustrate the expressive power gained by being able to state global constraints over these sorts. Finally, we briefly illustrate the sort system by applying it to some agreement phenomena and to problems of adjunct resolution.

1995

This paper describes some of the results of the project The Reusability of Grammatical Resources. The aim of the project is to extend current grammar formalisms with notational devices and constraint solvers in order to aid the development of reusable grammars. The project took the Advanced Linguistic Engineering Platform (ALEP) as its starting point. ALEP allows two levels of extension: additional syntactic expressions ("syntactic sugar") and specialised external constraint solvers. Our syntactic additions to ALEP comprise support for LFG coherence and completeness and an extended notation for phrase-structure rules. The project has developed solvers for set constraints, set operations, linear precedence constraints and guarded constraints. The extensions were formally specified and implemented as Prolog modules and hence have a wider applicability. These can be either used standalone or integrated within existing grammar formalisms. We have sucessfully integrated the all constraint solvers with the ProFIT typed feature system and these have been partially integrated into ALEP. ¡

This paper describes LiLFeS, an integrated unication-based programming system for linguistic formalisms based on typed feature structures, such as HPSG. The core engine of LiLFeS is an abstract machine developed for ecient handling of typed feature structures. Its basic design and optimization techniques are described. Performance comparisons between LiLFeS and other systems for typed feature structures show that LiL-FeS is more than 50 times faster than ALE, and competitive to ProFIT.

1981

For the past three years, John Hennessy has assisted my study of programming languages. He suggested that I investigate semantics, and later noted that the compiler generator might be feasible. As the research progressed, John helped me to focus on the most important problems. He made extensive comments on numerous drafts of this thesis and other papers.

1990

CLG is the latest member of a family of grammar formalisms centered around the notion of complex constraint expression for describing phrasal and iexical information and principles of language. Complex constrains can be expressed in a slightly restriced form of first order predicate logic, which makes CLG(2) well suited for expressing, amongst others, HPSG-style of grammars. A sound implementation of the formal semantics of CLG(2) is achieved'by resorting to delayed evaluation of non equational constraints.

2003

A problem for the development of constraint-based formalisms concerns (i) the maintainability of the grammars (ii) the modification of the programs according to this maintenance operations. We propose a solution to these difficulties by formally describing the global behaviour of the constraint satisfaction process and by expressing mathematically the locale functioning of each constraint. The proposed solution allows modifying the grammar without modifying the code of the program.

This paper describes the compilation techniques used in our HPSG(Pollard and Sag, 1987; Pollard and Sag, 1993)based parser. As the rst step, our parser builds up as fast as possible the parse trees which cover the whole input, by ignoring complex constraints. In the second phase, these ignored constraints are solved, but only for the completed trees covering the whole sentence. Our HPSG compiler generates code for the Common Lisp Object System (CLOS) which is used in the rst phase. The original grammar is written using feature structures and denite clause programs(Carpenter, 1992). The compiled code contains unication routines specialised for a given grammar and a xed parsing strategy, i.e., bottom-up parsing, as well as reduced constraints derived from the original grammar. Preliminary experiments show that our parser can be faster than a parser with conventional unication routines.

Lecture Notes in Computer Science, 2005

This paper presents the basis of Property Grammars, a fully constraintbased theory. In this approach, all kinds of linguistic information is represented by means of constraints. The constraint system constitutes then the core of the theory: it is the grammar, but it also constitutes, after evaluation for a given input, its description. Property Grammars is then a non-generative theory in the sense that no structure has to be build, only constraints are used both to represent linguistic information and to describe inputs. This paper describes the basic notions used in PG and proposes an account of long-distance dependencies, illustrating the expressive power of the formalism.