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OTTER 3.3 Reference Manual
"... by the United States Government and operated by The University of Chicago under the provisions of a contract with the Department of Energy. DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any a ..."
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by the United States Government and operated by The University of Chicago under the provisions of a contract with the Department of Energy. DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor The University of Chicago, nor any of their employees or officers, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privatelyowned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of document authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof, Argonne National Laboratory, or The University of Chicago. ii
Short Single Axioms for Boolean Algebra
 J. Automated Reasoning
, 2002
"... We present short single equational axioms for Boolean algebra in terms of disjunction and negation and in terms of the Sheffer stroke. Previously known single axioms for these theories are much longer than the ones we present. We show that there is no shorter axiom in terms of the Sheffer stroke tha ..."
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We present short single equational axioms for Boolean algebra in terms of disjunction and negation and in terms of the Sheffer stroke. Previously known single axioms for these theories are much longer than the ones we present. We show that there is no shorter axiom in terms of the Sheffer stroke than the ones we present. Automated deduction techniques were used for several different aspects of the work. Keywords: Boolean algebra, Sheffer stroke, single axiom 1. Background and
A Shortest 2Basis for Boolean Algebra in Terms of the Sheffer Stroke
 J. Automated Reasoning
, 2003
"... In this article, we present a short 2basis for Boolean algebra in terms of the Sheffer stroke and prove that no such 2basis can be shorter. We also prove that the new 2basis is unique (for its length) up to applications of commutativity. Our proof of the 2basis was found by using the method of p ..."
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In this article, we present a short 2basis for Boolean algebra in terms of the Sheffer stroke and prove that no such 2basis can be shorter. We also prove that the new 2basis is unique (for its length) up to applications of commutativity. Our proof of the 2basis was found by using the method of proof sketches and relied on the use of an automated reasoning program.
Conquering the Meredith Single Axiom
 J. Automated Reasoning
, 2000
"... For more than three and onehalf decades beginning in the early 1960s, a heavy emphasis on proof finding has been a key component of the Argonne paradigm, whose use has directly led to significant advances in automated reasoning and important contributions to mathematics and logic. The theorems t ..."
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For more than three and onehalf decades beginning in the early 1960s, a heavy emphasis on proof finding has been a key component of the Argonne paradigm, whose use has directly led to significant advances in automated reasoning and important contributions to mathematics and logic. The theorems that have served well range from the trivial to the deep, even including some that corresponded to open questions. Often the paradigm asks for a theorem whose proof is in hand but that cannot be obtained in a fully automated manner by the program in use. The theorem whose hypothesis consists solely of the Meredith single axiom for twovalued sentential (or propositional) calculus and whose conclusion is the Lukasiewicz threeaxiom system for that area of formal logic was just such a theorem. Featured in this article is the methodology that enabled the program OTTER to find the first fully automated proof of the cited theorem, a proof with the intriguing property that none of its steps...
Automating the search for elegant proofs
 J. Automated Reasoning
"... The research reported in this article was spawned by a colleague’s request to find an elegant proof (of a theorem from Boolean algebra) to replace his proof consisting of 816 deduced steps. The request was met by finding a proof consisting of 100 deduced steps. The methodology used to obtain the far ..."
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Cited by 8 (5 self)
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The research reported in this article was spawned by a colleague’s request to find an elegant proof (of a theorem from Boolean algebra) to replace his proof consisting of 816 deduced steps. The request was met by finding a proof consisting of 100 deduced steps. The methodology used to obtain the far shorter proof is presented in detail through a sequence of experiments. Although clearly not an algorithm, the methodology is sufficiently general to enable its use for seeking elegant proofs regardless of the domain of study. In addition to (usually) being more elegant, shorter proofs often provide the needed path to constructing a more efficient circuit, a more effective algorithm, and the like. The methodology relies heavily on the assistance of McCune’s automated reasoning program OTTER. Of the aspects of proof elegance, the main focus here is on proof length, with brief attention paid to the type of term present, the number of variables required, and the complexity of deduced steps. The methodology is iterative, relying heavily on the use of three strategies: the resonance strategy, the hot list strategy, and McCune’s ratio strategy. These strategies, as well as other features on which the methodology relies, do exhibit tendencies that can be exploited in the search for shorter proofs and for other objectives. To provide some insight regarding the value of the methodology, I discuss its successful application to
Flexible Reenactment of Proofs
 In Proc. 8th Portuguese Conference on Artificial Intelligence (EPIA97), LNAI 1323
, 1997
"... We present a method for making use of past proof experience called flexible reenactment (FR). FR is actually a searchguiding heuristic that uses past proof experience to create a search bias. Given a proof P of a problem solved previously that is assumed to be similar to the current problem A, FR ..."
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We present a method for making use of past proof experience called flexible reenactment (FR). FR is actually a searchguiding heuristic that uses past proof experience to create a search bias. Given a proof P of a problem solved previously that is assumed to be similar to the current problem A, FR searches for P and in the "neighborhood" of P in order to find a proof of A. This heuristic use of past experience has certain advantages that make FR quite profitable and give it a wide range of applicability. Experimental studies substantiate and illustrate this claim. This work was supported by the Deutsche Forschungsgemeinschaft (DFG). 2 1 INTRODUCTION 1 Introduction Automated deduction is essentially a search problem that gives rise to potentially infinite search spaces because of general undecidability. Despite these unfavorable conditions stateoftheart theorem provers have gained a remarkable level of performance mainly due to (problemspecific) searchguiding heuristics and...
Short equational bases for ortholattices
 Preprint ANL/MCSP10870903, Mathematics and Computer Science Division, Argonne National Laboratory, Argonne, IL
, 2004
"... Short single axioms for ortholattices, orthomodular lattices, and modular ortholattices are presented, all in terms of the Sheffer stroke. The ortholattice axiom is the shortest possible. Other equational bases in terms of the Sheffer stroke and in terms of join, meet, and complement are presented. ..."
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Short single axioms for ortholattices, orthomodular lattices, and modular ortholattices are presented, all in terms of the Sheffer stroke. The ortholattice axiom is the shortest possible. Other equational bases in terms of the Sheffer stroke and in terms of join, meet, and complement are presented. Proofs are omitted but are available in an associated technical report. Computers were used extensively to find candidates, reject candidates, and search for proofs that candidates are single axioms. The notion of computer proof is addressed. 1
Experiments concerning the Automated Search for Elegant Proofs
 Technical Memorandum ANL/MCSTM221, Mathematics and Computer Science Division, Argonne National Laboratory
, 1997
"... ..."
Heaps and Data Structures: A Challenge for Automated Provers
"... Software verification is one of the most prominent application areas for automatic reasoning systems, but their potential improvement is limited by shortage of good benchmarks. Current benchmarks are usually large but shallow, require decision procedures, or have soundness problems. In contrast, we ..."
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Software verification is one of the most prominent application areas for automatic reasoning systems, but their potential improvement is limited by shortage of good benchmarks. Current benchmarks are usually large but shallow, require decision procedures, or have soundness problems. In contrast, we propose a family of benchmarks in firstorder logic with equality which is scalable, relatively simple to understand, yet closely resembles difficult verification conditions stemming from realworld C code. Based on this benchmark, we present a detailed comparison of different heap encodings using a number of SMT solvers and ATPs. Our results led to a performance gain of an order of magnitude for the C code verifier VCC.