Towards Predicate Answer Set Programming via Coinductive Logic Programming

Abstract

Answer Set Programming (ASP) is a powerful paradigm based on logic programming for non-monotonic reasoning. Current ASP implementations are restricted to "grounded range-restricted function-free normal programs" and use an evaluation strategy that is "bottom-up" (i.e., not goal-driven). Recent introduction of coinductive Logic Programming (co-LP) has allowed the development of topdown goal evaluation strategies for ASP. In this paper we present this novel goaldirected, top-down approach to executing predicate answer set programs with co-LP. Our method eliminates the need for grounding, allows functions, and effectively handles a large class of predicate answer set programs including possibly infinite ones.

Infinite Computation, Co-induction and Computational Logic

“…We have designed and implemented the techniques and algorithms to execute propositional and predicate ASP programs. Our techniques are applicable to the full range of propositional answer set programs, but for predicate ASP we are restricted to programs that are call-consistent or order-consistent [19].…”

A Theoretical Perspective of Coinductive Logic Programming

“…There are at least three main reasons that make Prolog a suitable programming language for supporting coinductive programming [31,30,22]: its remarkably clean semantics, its built-in support for rational terms, and its declarative nature. Imperative languages lack abstraction mechanisms for defining and manipulating circular structures that avoid explicit use of references; for instance, in an object-oriented language, creating two objects pointing to each other through two fields requires at least three statements, because the field of the firstly created object can be correctly assigned only after the second object has been created.…”