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PROTEIN: A PROver with a Theory Extension Interface
 AUTOMATED DEDUCTION  CADE12, VOLUME 814 OF LNAI
, 1994
"... PROTEIN (PROver with a Theory Extension INterface) is a PTTPbased first order theorem prover over builtin theories. Besides various standardrefinements known for model elimination, PROTEIN also offers a variant of model elimination for casebased reasoning and which does not need contrapositives. ..."
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Cited by 41 (10 self)
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PROTEIN (PROver with a Theory Extension INterface) is a PTTPbased first order theorem prover over builtin theories. Besides various standardrefinements known for model elimination, PROTEIN also offers a variant of model elimination for casebased reasoning and which does not need contrapositives.
Model Elimination without Contrapositives and its Application to PTTP
 PROCEEDINGS OF CADE12, SPRINGER LNAI 814
, 1994
"... We give modifications of model elimination which do not necessitate the use of contrapositives. These restart model elimination calculi are proven sound and complete and their implementation by PTTP is depicted. The corresponding proof procedures are evaluated by a number of runtime experiments and ..."
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Cited by 22 (8 self)
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We give modifications of model elimination which do not necessitate the use of contrapositives. These restart model elimination calculi are proven sound and complete and their implementation by PTTP is depicted. The corresponding proof procedures are evaluated by a number of runtime experiments and they are compared to other well known provers. Finally we relate our results to other calculi, namely the connection method, modified problem reduction format and NearHorn Prolog.
Disjunctive Logic Programming: A Survey And Assessment
, 2002
"... We describe the elds of disjunctive logic programming and disjunctive deductive databases from the time of their inception to the current time. Contributions with respect to semantics, implementations and applications are surveyed. ..."
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Cited by 16 (0 self)
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We describe the elds of disjunctive logic programming and disjunctive deductive databases from the time of their inception to the current time. Contributions with respect to semantics, implementations and applications are surveyed.
A nearHorn Prolog for Compilation
 Computational Logic: Essays in Honor of Alan
, 1989
"... NearHorn Prolog is a logic programming language which extends Prolog to handle nonHorn clauses. It was designed with the goal of minimizing the performance loss for programs with very few nonHorn clauses, while preserving the Prolog format. In this paper, we present a version of nearHorn Prolog ..."
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Cited by 10 (4 self)
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NearHorn Prolog is a logic programming language which extends Prolog to handle nonHorn clauses. It was designed with the goal of minimizing the performance loss for programs with very few nonHorn clauses, while preserving the Prolog format. In this paper, we present a version of nearHorn Prolog that provides a stronger proof system than used by previous nearHorn procedures, and takes advantage of the preprocessing capability of compilers to reduce the accompanying performance penalty. In fact, for a sizable class of nonHorn programs the added inference rule strength incurs no performance penalty at all. In addition to describing this variant, called Inheritance nearHorn Prolog, we prove its soundness and (classical) completeness. 1 Introduction Prolog has been a very successful realization of the concept of logic programming, becoming a serious alternative to LISP as an AI language and enjoying considerable commercial success. However, it has also been clear that a single lan...
Elimination of Negation in a Logical Framework
, 2000
"... Logical frameworks with a logic programming interpretation such as hereditary Harrop formulae (HHF) [15] cannot express directly negative information, although negation is a useful specification tool. Since negationasfailure does not fit well in a logical framework, especially one endowed with ..."
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Cited by 10 (3 self)
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Logical frameworks with a logic programming interpretation such as hereditary Harrop formulae (HHF) [15] cannot express directly negative information, although negation is a useful specification tool. Since negationasfailure does not fit well in a logical framework, especially one endowed with hypothetical and parametric judgements, we adapt the idea of elimination of negation introduced in [21] for Horn logic to a fragment of higherorder HHF. This entails finding a middle ground between the Closed World Assumption usually associated with negation and the Open World Assumption typical of logical frameworks; the main technical idea is to isolate a set of programs where static and dynamic clauses do not overlap.
Analysis and Transformation of Proof Procedures
, 1994
"... Automated theorem proving has made great progress during the last few decades. Proofs of more and more difficult theorems are being found faster and faster. However, the exponential increase in the size of the search space remains for many theorem proving problems. Logic program analysis and transfo ..."
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Cited by 8 (2 self)
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Automated theorem proving has made great progress during the last few decades. Proofs of more and more difficult theorems are being found faster and faster. However, the exponential increase in the size of the search space remains for many theorem proving problems. Logic program analysis and transformation techniques have also made progress during the last few years and automated theorem proving can benefit from these techniques if they can be made applicable to general theorem proving problems. In this thesis we investigate the applicability of logic program analysis and transformation techniques to automated theorem proving. Our aim is to speed up theorem provers by avoiding useless search. This is done by detecting and deleting parts of the theorem prover and theory under consideration that are not needed for proving a given formula. The analysis and transformation techniques developed for logic programs can be applied in automated theorem proving via a programming technique called ...
Refinements of Theory Model Elimination and a Variant without Contrapositives
 University of Koblenz, Institute for Computer Science
, 1994
"... Theory Reasoning means to buildin certain knowledge about a problem domain into a deduction system or calculus, which is in our case model elimination. Several versions of theory model elimination (TME) calculi are presented and proven complete: on the one hand we have highly restricted versions of ..."
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Cited by 8 (6 self)
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Theory Reasoning means to buildin certain knowledge about a problem domain into a deduction system or calculus, which is in our case model elimination. Several versions of theory model elimination (TME) calculi are presented and proven complete: on the one hand we have highly restricted versions of total and partial TME. These restrictions allow (1) to keep fewer path literals in extension steps than in related calculi, and (2) discard proof attempts with multiple occurrences of literals along a path (i.e. regularity holds). On the other hand, we obtain by small modifications to TME versions which do not need contrapositives (a la NearHorn Prolog). We show that regularity can be adapted for these versions. The independence of the goal computation rule holds for all variants. Comparative runtime results for our PTTPimplementations are supplied. 1 Introduction The model elimination calculus (ME calculus) has been developed already in the early days of automated theorem proving [Lovel...
An Alternative Characterization of Disjunctive Logic Programs
 LOGIC PROGRAMMING: PROC. OF THE 1991 INT'L SYMP
, 1991
"... We present an alternative characterization of disjunctive logic programs. We first review Inheritance nearHorn Prolog (InHProlog), an intuitive and computationally effective procedure that extends Prolog using caseanalysis. We then describe a fixpoint characterization of disjunctive logic program ..."
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Cited by 8 (1 self)
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We present an alternative characterization of disjunctive logic programs. We first review Inheritance nearHorn Prolog (InHProlog), an intuitive and computationally effective procedure that extends Prolog using caseanalysis. We then describe a fixpoint characterization of disjunctive logic programs that is similarly based on caseanalysis. This fixpoint characterization closely corresponds to the InHProlog procedure, and so gives needed insight into the difficult problem of recognizing the minimal disjunctive answers obtainable from the procedure. Due to its caseanalysis nature, this characterization maintains a natural and close relationship to the standard characterization of Horn programs. It also gives added insight into the role of definite answers for disjunctive programs and enables one to neatly focus attention on the interesting class of definite (single atom) consequences.
A Disjunctive Positive Refinement of Model Elimination and its Application to Subsumption Deletion
 Journal of Automated Reasoning
, 1995
"... The Model Elimination (ME) calculus is a refutational complete, goaloriented calculus for firstorder clause logic. In this paper, we introduce a new variant called disjunctive positive ME (DPME); it improves on Plaisted's positive refinement of ME in that reduction steps are allowed only with p ..."
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Cited by 5 (0 self)
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The Model Elimination (ME) calculus is a refutational complete, goaloriented calculus for firstorder clause logic. In this paper, we introduce a new variant called disjunctive positive ME (DPME); it improves on Plaisted's positive refinement of ME in that reduction steps are allowed only with positive literals stemming from disjunctive clauses.