We discuss some approaches to declarative programming including functional programming, various logic programming languages and extensions, and definitional programming. In particular we discuss the programmers need and possibilities to influence the control part of programs. We also discuss some problems of the definitional programming language GCLA and try to find directions for future resear...

Automatic question answering (QA) has gained increasing interest in the last few years. Question-Answering systems return an answer rather than a document. Definitional questions are questions such as Who is Alexander Hamilton? or what are fractals? Looking at logs of web search engines definitional questions occur quite frequently, suggesting it is an important type of questions. Analysis of p...

This paper discusses two rules of definitional reflection: The “logical” version of definitional reflection as used in the extended logic programming language GCLA and the “ω”-version of definitional reflection as proposed by Eriksson and Girard. The logical version is a Left-introduction rule completely analogous to the Left-introduction rules for logical operators in Gentzen-style sequent sys...

Certain constraints that should be interpreted as definitions or quasi-definitions can cause prediction problems for logics of action. Standard ways to avoid them rely on notions of priority in the minimization of fluent change. We offer an alternative approach based on belief revision. Revision is performed on the reduct of the system theory after isolating definitions, and the revised theory ...

BACKGROUND Narrative therapy (White & Epston, 1990) was developed as an approach to counselling, as a response to the power relations that influence people's lives. Its use with people who stutter has been documented. A basic tenet of narrative therapy is that the dominant problem-saturated narrative is challenged by externalizing the problem, in due course facilitating development of an altern...

When we extend a type system, the relation between the original system and its extension is an important issue we want to understand. Conservative extension is a traditional relation we study with. But in some cases, like coercive subtyping, it is not strong enough to capture all the properties, more powerful relation between the systems is required. We bring the idea definitional extension fro...