---
title: "First-Order Expressibility and Boundedness of Disjunctive Logic Programs"
authors:
  - "Heng Zhang"
  - "Yan Zhang"
doi: ""
url: "https://ijcai.org/proceedings/2013/180"
pdf: "https://ijcai.org/proceedings/2013/0180.pdf"
venue: "Proceedings of the Twenty-Third International Joint Conference on Artificial Intelligence"
year: 2013
pages: "1198-1203"
track: ""
keywords:
---

# First-Order Expressibility and Boundedness of Disjunctive Logic Programs

Heng Zhang, Yan Zhang

*Proceedings of the Twenty-Third International Joint Conference on Artificial Intelligence*, pages 1198-1203.

## Abstract

In this paper, the fixed point semantics developed in [Lobo et al., 1992] is generalized to disjunctive logic programs with default negation and over arbitrary structures, and proved to coincide with the stable model semantics. By using the tool of ultraproducts, a preservation theorem, which asserts that a disjunctive logic program without default negation is bounded with respect to the proposed semantics if and only if it has a first-order equivalent, is then obtained. For the disjunctive logic programs with default negation, a sufficient condition assuring the first-order expressibility is also proposed.