---
title: "Defeasible Specifications in Action Theories"
authors:
  - "Chitta Baral"
  - "Jorge Lobo"
doi: ""
url: "https://ijcai.org/proceedings/1997/207"
pdf: "https://ijcai.org/proceedings/1997/0207.pdf"
venue: "Proceedings of the Fifteenth International Joint Conference on Artificial Intelligence"
year: 1997
pages: "1441-1445"
track: "Temporal Reasoning"
keywords:
---

# Defeasible Specifications in Action Theories

Chitta Baral, Jorge Lobo

*Proceedings of the Fifteenth International Joint Conference on Artificial Intelligence*, pages 1441-1445.

## Abstract

Recent research in formalizing effects of actions on a world in the presence of constraints have mostly concentrated on non-defeasible specifications , where the effect of actions and constraints are strictly specified. In this paper we show how to incorporate defeasibility into the specifications. In our approach we consider extensions of the high level language A of Gelfond and Lifschitz and introduce defeasible constraints and effect propositions. While direct semantics of A does not need a logical language, our semantics is defined using extended logic programming. This is due to the defeasibility of the specification.