40,947 research outputs found
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
The Football of Logic
An analogy is made between two rather different domains, namely: logic, and football. Starting from a comparative table between the two activities, an alternative explanation of logic is given in terms of players, ball, goal, and the like. Our main thesis is that, just as the task of logic is preserving truth from premises to the conclusion, footballers strive to keep the ball as far as possible until the opposite goal. Assuming this analogy may help think about logic in the same way as in dialogical logic, but it should also present truth-values in an alternative sense of speech-acts occurring in a dialogue. The relativity of truth-values is focused by this way, thereby leading to an additional way of logical pluralism
A Spectrum of Applications of Automated Reasoning
The likelihood of an automated reasoning program being of substantial
assistance for a wide spectrum of applications rests with the nature of the
options and parameters it offers on which to base needed strategies and
methodologies. This article focuses on such a spectrum, featuring W. McCune's
program OTTER, discussing widely varied successes in answering open questions,
and touching on some of the strategies and methodologies that played a key
role. The applications include finding a first proof, discovering single
axioms, locating improved axiom systems, and simplifying existing proofs. The
last application is directly pertinent to the recently found (by R. Thiele)
Hilbert's twenty-fourth problem--which is extremely amenable to attack with the
appropriate automated reasoning program--a problem concerned with proof
simplification. The methodologies include those for seeking shorter proofs and
for finding proofs that avoid unwanted lemmas or classes of term, a specific
option for seeking proofs with smaller equational or formula complexity, and a
different option to address the variable richness of a proof. The type of proof
one obtains with the use of OTTER is Hilbert-style axiomatic, including details
that permit one sometimes to gain new insights. We include questions still open
and challenges that merit consideration.Comment: 13 page
A Parallel semantics for normal logic programs plus time
It is proposed that Normal Logic Programs with an explicit time ordering are a suitable basis for a general purpose parallel programming language. Examples show that such a language can accept real-time external inputs and outputs, and mimic assignment, all without departing from its pure logical semantics. This paper describes a fully incremental bottom-up interpreter that supports a wide range of parallel execution strategies and can extract significant potential parallelism from programs with complex dependencies
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