9,130 research outputs found
Embedding Defeasible Logic into Logic Programming
Defeasible reasoning is a simple but efficient approach to nonmonotonic
reasoning that has recently attracted considerable interest and that has found
various applications. Defeasible logic and its variants are an important family
of defeasible reasoning methods. So far no relationship has been established
between defeasible logic and mainstream nonmonotonic reasoning approaches.
In this paper we establish close links to known semantics of logic programs.
In particular, we give a translation of a defeasible theory D into a
meta-program P(D). We show that under a condition of decisiveness, the
defeasible consequences of D correspond exactly to the sceptical conclusions of
P(D) under the stable model semantics. Without decisiveness, the result holds
only in one direction (all defeasible consequences of D are included in all
stable models of P(D)). If we wish a complete embedding for the general case,
we need to use the Kunen semantics of P(D), instead.Comment: To appear in Theory and Practice of Logic Programmin
Defeasible Logic Programming: An Argumentative Approach
The work reported here introduces Defeasible Logic Programming (DeLP), a
formalism that combines results of Logic Programming and Defeasible
Argumentation. DeLP provides the possibility of representing information in the
form of weak rules in a declarative manner, and a defeasible argumentation
inference mechanism for warranting the entailed conclusions.
In DeLP an argumentation formalism will be used for deciding between
contradictory goals. Queries will be supported by arguments that could be
defeated by other arguments. A query q will succeed when there is an argument A
for q that is warranted, ie, the argument A that supports q is found undefeated
by a warrant procedure that implements a dialectical analysis.
The defeasible argumentation basis of DeLP allows to build applications that
deal with incomplete and contradictory information in dynamic domains. Thus,
the resulting approach is suitable for representing agent's knowledge and for
providing an argumentation based reasoning mechanism to agents.Comment: 43 pages, to appear in the journal "Theory and Practice of Logic
Programming
Defeasible logic programming: language definition, operational semantics, and parallelism
This thesis defines Defeasible Logic Programming and provides a concrete specification of this new language through its operational semantics. Defeasible Logic Programming, or DeLP for short, has been defined based on the Logic Programming paradigm and considering features of recent developments in the area of Defeasible Argumentation. DeLP relates and improves many aspects of the areas of Logic Programming, Defeasible Argumentation, Intelligent Agents, and Parallel Logic ProgrammingFacultad de Informátic
Argumentation Semantics for Defeasible Logics
Defeasible logic is a simple but efficient rule-based non-monotonic logic. It has powerful implementations and shows promise to be applied in the areas of legal reasoning and the modelling of business rules. So far defeasible logic has been defined only proof-theoretically. Argumentation-based semantics have become popular in the area of logic programming. In this paper we give an argumentation-based semantics for defeasible logic. Recently it has been shown that a family of approaches can be built around defeasible logic, in which different intuitions can be followed. In this paper we present an argumentation-based semantics for an ambiguity propagating logic, too. Further defeasible logics can be characterised in a similar way
Defeasible logic programming: language definition, operational semantics, and parallelism
This thesis defines Defeasible Logic Programming and provides a concrete specification of this new language through its operational semantics. Defeasible Logic Programming, or DeLP for short, has been defined based on the Logic Programming paradigm and considering features of recent developments in the area of Defeasible Argumentation. DeLP relates and improves many aspects of the areas of Logic Programming, Defeasible Argumentation, Intelligent Agents, and Parallel Logic ProgrammingFacultad de Informátic
Handling Defeasibilities in Action Domains
Representing defeasibility is an important issue in common sense reasoning.
In reasoning about action and change, this issue becomes more difficult because
domain and action related defeasible information may conflict with general
inertia rules. Furthermore, different types of defeasible information may also
interfere with each other during the reasoning. In this paper, we develop a
prioritized logic programming approach to handle defeasibilities in reasoning
about action. In particular, we propose three action languages {\cal AT}^{0},
{\cal AT}^{1} and {\cal AT}^{2} which handle three types of defeasibilities in
action domains named defeasible constraints, defeasible observations and
actions with defeasible and abnormal effects respectively. Each language with a
higher superscript can be viewed as an extension of the language with a lower
superscript. These action languages inherit the simple syntax of {\cal A}
language but their semantics is developed in terms of transition systems where
transition functions are defined based on prioritized logic programs. By
illustrating various examples, we show that our approach eventually provides a
powerful mechanism to handle various defeasibilities in temporal prediction and
postdiction. We also investigate semantic properties of these three action
languages and characterize classes of action domains that present more
desirable solutions in reasoning about action within the underlying action
languages.Comment: 49 pages, 1 figure, to be appeared in journal Theory and Practice
Logic Programmin
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