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17
A Proof Procedure Using Connection Graphs
 JACM
, 1975
"... ABSTRACT. Various deficiencies of resolution systems are investigated and a new theoremproving system designed to remedy those deficiencms is presented The system is notable for eliminating redundancies present in SLresolutlon, for incorporating preprocessing procedures, for liberahzing the order ..."
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Cited by 76 (5 self)
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ABSTRACT. Various deficiencies of resolution systems are investigated and a new theoremproving system designed to remedy those deficiencms is presented The system is notable for eliminating redundancies present in SLresolutlon, for incorporating preprocessing procedures, for liberahzing the order in which subgoals can be activated, for incorporating multidirectmnal searches, and for giving immediate access to pairs of clauses which resolve Examples of how the new system copes with the defic2encies of other theoremproving systems are chosen from the areas of predicate logic programming and language parsing. The paper emphasizes the historical development of the new system, beginning as a supplement to SLresolution in the form of classificatmn trees and incorporating an analogue of the Waltz algorithm for picture Interpretation The paper ends with a discussion of the opportunities for using lookahead to guide the search for proofs
tps: A theorem proving system for classical type theory
 Journal of Automated Reasoning
, 1996
"... This is a description of TPS, a theorem proving system for classical type theory (Church’s typed λcalculus). TPS has been designed to be a general research tool for manipulating wffs of first and higherorder logic, and searching for proofs of such wffs interactively or automatically, or in a comb ..."
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Cited by 71 (6 self)
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This is a description of TPS, a theorem proving system for classical type theory (Church’s typed λcalculus). TPS has been designed to be a general research tool for manipulating wffs of first and higherorder logic, and searching for proofs of such wffs interactively or automatically, or in a combination of these modes. An important feature of TPS is the ability to translate between expansion proofs and natural deduction proofs. Examples of theorems which TPS can prove completely automatically are given to illustrate certain aspects of TPS’s behavior and problems of theorem proving in higherorder logic. 7
Proof Search in the Intuitionistic Sequent Calculus
 11th International Conference on Automated Deduction
, 1991
"... The use of Herbrand functions (more popularly known as Skolemization) plays an important role in classical theorem proving and logic programming. We define a notion of Herbrand functions for the full intuitionistic predicate calculus. The definition is based on the view that the prooftheoretic role ..."
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Cited by 42 (1 self)
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The use of Herbrand functions (more popularly known as Skolemization) plays an important role in classical theorem proving and logic programming. We define a notion of Herbrand functions for the full intuitionistic predicate calculus. The definition is based on the view that the prooftheoretic role of Herbrand functions (to replace universal quantifiers), and of unification (to find instances corresponding to existential quantifiers), is to ensure that the eigenvariable conditions on a sequent proof are respected. The propositional impermutabilities that arise in the intuitionistic but not the classical sequent calculus motivate a generalization of the classical notion of Herbrand functions. Proof search using generalized Herbrand functions also provides a framework for generalizing logic programming to subsets of intuitionistic logic that are larger than Horn clauses. The search procedure described here has been implemented and observed to work effectively in practice. The generaliza...
Mechanical Proofs about Computer Programs
, 1984
"... The Gypsy verification environment is a large computer program that supports the development of software systems and formal, mathematical proofs about their behavior. The environment provides conventional development tools, such as a parser for the Gypsy language, an editor and a compiler. These are ..."
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Cited by 28 (0 self)
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The Gypsy verification environment is a large computer program that supports the development of software systems and formal, mathematical proofs about their behavior. The environment provides conventional development tools, such as a parser for the Gypsy language, an editor and a compiler. These are used to evolve a library of components that define both the software and precise specifications about its desired behavior. The environment also has a verification condition generator that automatically transforms a software component and its specification into logical formulas which are sufficient to prove that the component always runs according to specification. Facilities for constructing formal, mechanical proofs of these formulas also are provided. Many of these proofs are completed automatically without human intervention. The capabilities of the Gypsy system and the results of its applications are discussed.
TPS: A TheoremProving System for Classical Type Theory
, 1996
"... . This is description of TPS, a theoremproving system for classical type theory (Church's typed #calculus). TPS has been designed to be a general research tool for manipulating wffs of first and higherorder logic, and searching for proofs of such wffs interactively or automatically, or in a comb ..."
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Cited by 16 (0 self)
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. This is description of TPS, a theoremproving system for classical type theory (Church's typed #calculus). TPS has been designed to be a general research tool for manipulating wffs of first and higherorder logic, and searching for proofs of such wffs interactively or automatically, or in a combination of these modes. An important feature of TPS is the ability to translate between expansion proofs and natural deduction proofs. Examples of theorems that TPS can prove completely automatically are given to illustrate certain aspects of TPS's behavior and problems of theorem proving in higherorder logic. AMS Subject Classification: 0304, 68T15, 03B35, 03B15, 03B10. Key words: higherorder logic, type theory, mating, connection, expansion proof, natural deduction. 1. Introduction TPS is a theoremproving system for classical type theory ## (Church's typed #calculus [20]) which has been under development at Carnegie Mellon University for a number years. This paper gives a general...
Program verification
 Journal of Automated Reasoning
, 1985
"... Computer programs may be regarded as formal mathematical objects whose properties are subject to mathematical proof. Program verification is the use of formal, mathematical techniques to debug software and software specifications. 1. Code Verification How are the properties of computer programs prov ..."
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Cited by 14 (4 self)
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Computer programs may be regarded as formal mathematical objects whose properties are subject to mathematical proof. Program verification is the use of formal, mathematical techniques to debug software and software specifications. 1. Code Verification How are the properties of computer programs proved? We discuss three approaches in this article: inductive invariants, functional semantics, and explicit semantics. Because the first approach has received by far the most attention, it has produced the most impressive results to date. However, the field is now moving away from the inductive invariant approach. 1.1. Inductive Assertions The socalled FloydHoare inductive assertion method of program verification [25, 33] has its roots in the classic Goldstine and von Neumann reports [53] and handles the usual kind of programming language, of which FORTRAN is perhaps the best example. In this style of verification, the specifier "annotates " certain points in the program with mathematical assertions that are supposed to describe relations that hold between the program variables and the initial input values each time "control " reaches the annotated point. Among these assertions are some that characterize acceptable input and the desired output. By exploring all possible paths from one assertion to the next and analyzing the effects of intervening program statements it is possible to reduce the correctness of the program to the problem of proving certain derived formulas called verification conditions. Below we illustrate the idea with a simple program for computing the factorial of its integer input N flowchart assertion start with input(N) input N A: = 1 N = 0 yes stop with? answer A
Writing PVS proof strategies
 Design and Application of Strategies/Tactics in Higher Order Logics (STRATA 2003), number CP2003212448 in NASA Conference Publication
, 2003
"... Abstract. PVS (Prototype Verification System) is a comprehensive framework for writing formal logical specifications and constructing proofs. An interactive proof checker is a key component of PVS. The capabilities of this proof checker can be extended by defining proof strategies that are similar t ..."
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Cited by 6 (1 self)
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Abstract. PVS (Prototype Verification System) is a comprehensive framework for writing formal logical specifications and constructing proofs. An interactive proof checker is a key component of PVS. The capabilities of this proof checker can be extended by defining proof strategies that are similar to LCFstyle tactics. Commonly used proof strategies include those for discharging typechecking proof obligations, simplification and rewriting using decision procedures, and various forms of induction. We describe the basic building blocks of PVS proof strategies and provide a pragmatic guide for writing sophisticated strategies. 1
The Creation and Use of a Knowledge Base of Mathematical Theorems and Definitions
, 1995
"... IPR is an automatic theoremproving system intended particularly for use in higherlevel mathematics. It discovers the proofs of theorems in mathematics applying known theorems and definitions. Theorems and definitions are stored in the knowledge base in the form of sequents rather than formulas or ..."
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Cited by 2 (2 self)
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IPR is an automatic theoremproving system intended particularly for use in higherlevel mathematics. It discovers the proofs of theorems in mathematics applying known theorems and definitions. Theorems and definitions are stored in the knowledge base in the form of sequents rather than formulas or rewrite rules. Because there is more easilyaccessible information in a sequent than there is in the formula it represents, a simple algorithm can be used to search the knowledge base for the most useful theorem or definition to be used in the theoremproving process. This paper describes how the sequents in the knowledge base are formed from theorems stated by the user and how the knowledge base is used in the theoremproving process. An example of a theorem proved and the English proof output are also given. 1 Introduction The motivating goal behind this work is to develop a theoremproving system which will be useful to both an expert and a nonexpert in the attempt to prove theorems in ...
Discoveries and Experiments in the Automation of Mathematical Reasoning
, 2002
"... vii List of Figures xii Chapter 1. ..."