Epistemic Answer Set Programming

Abstract

This paper introduces a new epistemic extension of answer set programming (\(\mathsf {ASP}\)) called epistemic ASP (\(\mathsf {E\text {-}\mathsf {ASP}}\)). Then, it compares \(\mathsf {E\text {-}\mathsf {ASP}}\) with existing approaches, showing the advantages and the novelties of the new semantics and discusses which formalisms provide more intuitive results: compared to Gelfond’s epistemic specifications (\(\mathsf {ES}\)), \(\mathsf {E\text {-}\mathsf {ASP}}\) defines a simpler, but sufficiently strong language. Its epistemic view semantics is a natural and more standard generalisation of \(\mathsf {ASP}\)’s original answer set semantics, so it allows for \(\mathsf {ASP}\)’s previous language extensions. Moreover, compared to all semantics proposals in the literature, epistemic view semantics facilitates understanding of the intuitive meaning of epistemic logic programs and solves unintended results discussed in the literature, especially for epistemic logic programs including constraints.