this paper gives a brief high-level description of the implementation of a disjunctive logicprogramming system referred to as DisLoP. this system is a result of research activities of the Disjunctive logic Programmin...
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ISBN:
(纸本)3540632557
this paper gives a brief high-level description of the implementation of a disjunctive logicprogramming system referred to as DisLoP. this system is a result of research activities of the Disjunctive logicprogramming-project (funded by Deutsche Forschungs-Gemeinschaft), undertaken by the University of Koblenz since July 1995.
In this paper we introduce regression-based pre-and postdiction procedures for PMON, a nonmonotonic logic for action and change with explicit time. We also provide an in depth analysis of problems with regression that...
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ISBN:
(纸本)1558604804
In this paper we introduce regression-based pre-and postdiction procedures for PMON, a nonmonotonic logic for action and change with explicit time. We also provide an in depth analysis of problems with regression that occur when nondeterministic actions are introduced. We do this by employing Dijkstra's weakest liberal precondition operator, wlp. the presented work is related to recent work by Lin in the situation calculus, and we identify and deal withthree problems with his approach. Our conjecture is that our approach can be mapped back to the situation calculus.
Unfailing completion is a commonly used technique for equational reasoning. For equational problems with associative and commutative functions, unfailing completion often generates a large number of rewrite rules. By ...
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Unfailing completion is a commonly used technique for equational reasoning. For equational problems with associative and commutative functions, unfailing completion often generates a large number of rewrite rules. By comparing it with a ground completion procedure, we show that many of the rewrite rules generated are redundant. A set of consistency constraints is formulated to detect redundant rewrite rules. We propose a new completion algorithm, consistent unfailing completion, in which only consistent rewrite rules are used for critical pair generation and rewriting. Our approach does not need to use flattened terms. thus it avoids the double exponential worst case complexity of AC unification. It also allows the use of more flexible termination orderings. We present some sufficient conditions for detecting inconsistent rewrite rules. the proposed algorithm is implemented in PROLOG.
this paper presents a method to generate nonmonotonic rules with exceptions from positive/negative examples and background knowledge in Inductive logicprogramming. We adopt extended logic programs as the form of prog...
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ISBN:
(纸本)1558604804
this paper presents a method to generate nonmonotonic rules with exceptions from positive/negative examples and background knowledge in Inductive logicprogramming. We adopt extended logic programs as the form of programs to be learned, where two kinds of negation-negation as failure and classical negation-are effectively used in the presence of incomplete information. While default rules are generated as specialization of general rules that cover positive examples, exceptions to general rules are identified from negative examples and are then generalized to rules for cancellation of defaults. We implemented the learning system LELP based on the proposed method. In LELP, when the numbers of positive and negative examples are very close, either parallel default rules with positive and negative consequents or nondeterministic rules are learned, Moreover, hierarchical defaults can also be learned by recursively calling the exception identification algorithm.
this paper presents the type-oriented relational learner RHB+. Attaching type information to hypotheses is effective in avoiding overgeneralization as well as enhancing readability and comprehensibility. In many areas...
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ISBN:
(纸本)1558604804
this paper presents the type-oriented relational learner RHB+. Attaching type information to hypotheses is effective in avoiding overgeneralization as well as enhancing readability and comprehensibility. In many areas, such as NLP, type information is actually available, while negative examples are not. Unfortunately, learning performance is usually poor if types are attached when only positive examples are available. RHB+ makes use of type information to efficiently compute informativity from positive examples only and to judge a stopping condition. the new technique of dynamic type restriction by positive examples lets covered positive examples decide the types appropriate for the current clause. the current version of RHB+, written in the typed logicprogramming language LIFE, directly manipulates types as structured background knowledge when operations related to types are required. these features make RHB+ efficient and effective in attaching types selected from thousands of possible types, this leads to advantages over several previous learners, such as FOIL and PROGOL. Experimental results demonstrate RHB+'s fine performance for bothartificial and real data.
A general framework for revision of nonmonotonic theories is presented. this framework can be applied if the intended nonmonotonic semantics is not (weakly) cumulative. For weaker-semantics, it is shown that revision ...
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ISBN:
(纸本)3540632557
A general framework for revision of nonmonotonic theories is presented. this framework can be applied if the intended nonmonotonic semantics is not (weakly) cumulative. For weaker-semantics, it is shown that revision by contraction is not possible whenever the intended semantics satisfies Weak Cut and revision by expansion fails whenever Weak (Cautious) Monotony fails. Furthermore, it turns out that revision by expansion can be used to test whether the framework can be applied successfully and we analyse the case for logicprogramming.
Although it has been shown that non-monotonic reasoning is presumably harder than classical reasoning, there are cases where a non-monotonic treatment actually simplifies matters. Indeed, one of the reasons for consid...
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ISBN:
(纸本)3540632557
Although it has been shown that non-monotonic reasoning is presumably harder than classical reasoning, there are cases where a non-monotonic treatment actually simplifies matters. Indeed, one of the reasons for considering non-monotonic systems is the hope of speeding up reasoning, and not to slow it down. In this paper, we consider proof lengths in a cut-free sequent calculus, and we show that the application of circumscription (or completion) to certain first-order formulae leads to a non-elementary speed-up of proof length. this is possible because the introduction of the completion formula can simulate the cut rule.
this paper investigates separated autoepistemic logic which is a generalization of Moore's autoepistemic logic with separate modalities for belief and disbelief. Along the separation of beliefs and disbeliefs, the...
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ISBN:
(纸本)3540632557
this paper investigates separated autoepistemic logic which is a generalization of Moore's autoepistemic logic with separate modalities for belief and disbelief. Along the separation of beliefs and disbeliefs, the relationship between autoepistemic logic and default logic becomes very intuitive. Straightforward ways of translating default theories into separated autoepistemic theories and back are presented. these translations are shown to preserve a variety of semantics of default theories such as those based on default extensions, weak extensions and stationary extensions. these classes of extensions are captured by their analogs in separated autoepistemic logic, and vice versa. A particular novelty of the approach is that a reasonable notion of separated stationary expansions can be established.
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