A Paraconsistent ASP-like Language with Tractable Model Generation

TL;DR

This paper introduces 4SP, a new ASP-like language that combines ASP and paraconsistent logic to enable tractable model generation, addressing the intractability of answer set computation in traditional ASP.

Contribution

The paper proposes 4SP, a novel rule language that ensures polynomial-time model generation by integrating paraconsistent reasoning with ASP-like syntax.

Findings

4SP allows polynomial-time model generation.

4SP extends ASP with paraconsistent features.

Relationships among 4SP, ASP, and 4QL are established.

Abstract

Answer Set Programming (ASP) is nowadays a dominant rule-based knowledge representation tool. Though existing ASP variants enjoy efficient implementations, generating an answer set remains intractable. The goal of this research is to define a new \asp-like rule language, 4SP, with tractable model generation. The language combines ideas of ASP and a paraconsistent rule language 4QL. Though 4SP shares the syntax of \asp and for each program all its answer sets are among 4SP models, the new language differs from ASP in its logical foundations, the intended methodology of its use and complexity of computing models. As we show in the paper, 4QL can be seen as a paraconsistent counterpart of ASP programs stratified with respect to default negation. Although model generation of well-supported models for 4QL programs is tractable, dropping stratification makes both 4QL and ASP intractable. To retain tractability while allowing non-stratified programs, in 4SP we introduce trial expressions interlacing programs with hypotheses as to the truth values of default negations. This allows us to develop a~model generation algorithm with deterministic polynomial time complexity. We also show relationships among 4SP, ASP and 4QL.