163 research outputs found
A Defeasible Logic of Institutional Agency
A non-monotonic logic of institutional agency is defined combining a computationally oriented non-monotonic system (Defeasible Logic) and intentional notions of agency
Labelled Modal Sequents
In this paper we present a new labelled sequent calculus for modal logic. The proof method works with a more ``liberal'' modal language which allows inferential steps where different formulas refer to different labels without moving to a particular world and there computing if the consequence holds. World-paths can be composed, decomposed and manipulated through unification algorithms and formulas in different worlds can be compared even if they are sub-formulas which do not depend directly on the main connective. Accordingly, such a sequent system can provide a general definition of modal consequence relation. Finally, we briefly sketch a proof of the soundness and completeness results
Modelling Contracts Using RuleML
This paper presents an approach for the specification and implementation of e-contracts for Web monitoring. This is done in the setting of RuleML. We argue that monitoring contract execution requires also a logical account of deontic concepts and of violations. Accordingly, RuleML is extended to cover these aspects
Computing Strong and Weak Permissions in Defeasible Logic
In this paper we propose an extension of Defeasible Logic to represent and
compute three concepts of defeasible permission. In particular, we discuss
different types of explicit permissive norms that work as exceptions to
opposite obligations. Moreover, we show how strong permissions can be
represented both with, and without introducing a new consequence relation for
inferring conclusions from explicit permissive norms. Finally, we illustrate
how a preference operator applicable to contrary-to-duty obligations can be
combined with a new operator representing ordered sequences of strong
permissions which derogate from prohibitions. The logical system is studied
from a computational standpoint and is shown to have liner computational
complexity
Logic of Violations: A Gentzen System for Reasoning with Contrary-To-Duty Obligations
In this paper we present a Gentzen system for reasoning with contrary-to-duty obligations. The intuition behind the system is that a contrary-to-duty is a special kind of normative exception. The logical machinery to formalise this idea is taken from substructural logics and it is based on the definition of a new non-classical connective capturing the notion of reparational obligation. Then the system is tested against well-known contrary-to-duty paradoxes
Logic of Violations: A Gentzen System for Reasoning with Contrary-To-Duty Obligations
In this paper we present a Gentzen system for reasoning with contrary-to-duty obligations. The intuition behind the system is that a contrary-to-duty is a special kind of normative exception. The logical machinery to formalise this idea is taken from substructural logics and it is based on the definition of a new non-classical connective capturing the notion of reparational obligation. Then the system is tested against well-known contrary-to-duty paradoxes
Changing Legal Systems: Abrogation and Annulment. Part II: Temporalised Defeasible Logic
Slides of the talk given at NorMAS 2008. Luxembourg, 15 July 200
A Computational Framework for Non-Monotonic Agency, Institutionalised Power and Multi-Agent Systems
This work provides a first computational framework to capture some of the theoretical intuitions developed by the present authors and other colleagues. More precisely, in this paper we propose a computationally oriented model of institutional agency based on Defeasible Logic. The focus here is on the notions of counts-as link and on those of attempt and of personal and direct action to realise states of affairs
A Gentzen System for Reasoning with Contrary-To-Duty Obligations: A Preliminary Study
In this paper we present a Gentzen system for reasoning with contrary-to-duty obligations. The intuition behind the system is that a contrary-to-duty is a special kind of normative exception. The logical machinery to formalize this idea is taken from substructural logics and it is based on the definition of a new non-classical connective capturing the notion of reparational obligation. Then the system is tested against well-known contrary-to-duty paradoxe
- …