London, Ralph L.
Overview
Works:  20 works in 48 publications in 1 language and 57 library holdings 

Roles:  Author 
Classifications:  HF5548.5.A4, 510.785 
Publication Timeline
.
Most widely held works by
Ralph L London
Abstraction and verification in Alphard : a symbol table example by
Ralph L London(
Book
)
6 editions published in 1976 in English and held by 9 WorldCat member libraries worldwide
The design of the Alphard programming language has been strongly influenced by ideas from the areas of programming methodology and formal program verification. In this paper we design, implement, and verify a general symbol table mechanism. This example is rich enough to allow us to illustrate the use as well as the definition of programmerdefined abstractions. The verification illustrates the power of the form to simplify proofs by providing strong specifications of such abstractions. (Author)
6 editions published in 1976 in English and held by 9 WorldCat member libraries worldwide
The design of the Alphard programming language has been strongly influenced by ideas from the areas of programming methodology and formal program verification. In this paper we design, implement, and verify a general symbol table mechanism. This example is rich enough to allow us to illustrate the use as well as the definition of programmerdefined abstractions. The verification illustrates the power of the form to simplify proofs by providing strong specifications of such abstractions. (Author)
Abstraction and verification in Alphard : iteration and generators by
Mary Shaw(
Book
)
4 editions published in 1976 in English and held by 8 WorldCat member libraries worldwide
The Alphard form provides the programmer with a great deal of control over the implementation of abstract data types. In this report we extend the abstraction techniques from simple data representation and function definition to the iteration statement, the most important point of interaction between data and the control structure of the language itself. We introduce a means of specializing Alphard's loops to operate on abstract entities without explicit dependence on the representation of those entities. We develop specification and verification techniques that allow the properties of such iterations to be expressed in the form of proof rules. We also provide a means of showing that a generator will terminate and obtain results for common special cases that are essentially identical to the corresponding constructs in other languages. (Author)
4 editions published in 1976 in English and held by 8 WorldCat member libraries worldwide
The Alphard form provides the programmer with a great deal of control over the implementation of abstract data types. In this report we extend the abstraction techniques from simple data representation and function definition to the iteration statement, the most important point of interaction between data and the control structure of the language itself. We introduce a means of specializing Alphard's loops to operate on abstract entities without explicit dependence on the representation of those entities. We develop specification and verification techniques that allow the properties of such iterations to be expressed in the form of proof rules. We also provide a means of showing that a generator will terminate and obtain results for common special cases that are essentially identical to the corresponding constructs in other languages. (Author)
Abstraction and verification in Alphard : introduction to language and methodology by
William Allan Wulf(
Book
)
5 editions published in 1976 in English and held by 8 WorldCat member libraries worldwide
Alphard is a programming language whose goals include supporting both the development of wellstructured programs and the formal verification of these programs. This paper attempts to capture the symbiotic influence of these two goals on the design of the language. To that end the language description is interleaved with the presentation of a proof technique and discussion of programming methodology. Examples to illustrate both the language and the verification technique are included. (Author)
5 editions published in 1976 in English and held by 8 WorldCat member libraries worldwide
Alphard is a programming language whose goals include supporting both the development of wellstructured programs and the formal verification of these programs. This paper attempts to capture the symbiotic influence of these two goals on the design of the language. To that end the language description is interleaved with the presentation of a proof technique and discussion of programming methodology. Examples to illustrate both the language and the verification technique are included. (Author)
Correctness of Two Compilers for a Lisp Subset by
Ralph L London(
Book
)
6 editions published in 1971 in English and Undetermined and held by 6 WorldCat member libraries worldwide
Using mainly structural induction, proofs of correctness of each of two running Lisp compilers for the PDP10 computer are given. Indluded are the rationale for presenting these proofs, a discussion of the proofs, and the changes needed to the second compiler to complete its proof. (Author)
6 editions published in 1971 in English and Undetermined and held by 6 WorldCat member libraries worldwide
Using mainly structural induction, proofs of correctness of each of two running Lisp compilers for the PDP10 computer are given. Indluded are the rationale for presenting these proofs, a discussion of the proofs, and the changes needed to the second compiler to complete its proof. (Author)
A computer program for discovering and proving sequential recognition rules for wellformed formulas defined by a Backus normal
form grammar by
Ralph L London(
Book
)
4 editions published in 1964 in English and held by 5 WorldCat member libraries worldwide
A report is presented based upon a computer program which will discover rules for the recognition of grammatical strings when given a simple Backus Normal Form grammar. The program attempts to prove that these rules are both necessary and sufficient to characterize grammatical strings. The main mathematical techniques that are mechanized are induction and case analysis. In addition the program is capable of producing counterexamples. Since the program is writing proofs, several (meta )proofs are included asserting the correctness of the produced proofs. The program exists for two reasons. First, it will construct a recognizer for some Backus Normal Form grammars and provide a proof of the validity of the recognizer. Second, its domain is a convenient one for proving theorems by machines, especially those whose proofs may use fairly involved case analysis. The overall strategy used to discover the rules and to prove them valid is described, followed by a discussion of the program organization and internal representations. Limitations and possible improvements to the present program are mentioned. An assessment is made of the mathematical accomplishments of the program and the value of the program as a mathematical aid. An appendix presents the output of four examples of program runs. (Author)
4 editions published in 1964 in English and held by 5 WorldCat member libraries worldwide
A report is presented based upon a computer program which will discover rules for the recognition of grammatical strings when given a simple Backus Normal Form grammar. The program attempts to prove that these rules are both necessary and sufficient to characterize grammatical strings. The main mathematical techniques that are mechanized are induction and case analysis. In addition the program is capable of producing counterexamples. Since the program is writing proofs, several (meta )proofs are included asserting the correctness of the produced proofs. The program exists for two reasons. First, it will construct a recognizer for some Backus Normal Form grammars and provide a proof of the validity of the recognizer. Second, its domain is a convenient one for proving theorems by machines, especially those whose proofs may use fairly involved case analysis. The overall strategy used to discover the rules and to prove them valid is described, followed by a discussion of the program organization and internal representations. Limitations and possible improvements to the present program are mentioned. An assessment is made of the mathematical accomplishments of the program and the value of the program as a mathematical aid. An appendix presents the output of four examples of program runs. (Author)
An Interactive Program Verification System by
Donald I Good(
Book
)
5 editions published between 1974 and 1975 in English and Undetermined and held by 4 WorldCat member libraries worldwide
This paper is an initial progress report on the development of an interactive system for verifying that computer programs meet given formal specifications. The system is based on the conventional inductive assertion method: given a program and its specifications, the object is to generate the verification conditions, simplify them, and prove what remains. This system addresses two aspects of software improvement of extreme importance to the military: increase in the quality of software and decrease in the cost of producing highquality software. A general description is given of the overall design philosophy, structure, and functional components of the system, and a simple sorting program is used to illustrate both the behavior of major system components and the type of user interaction the system provides
5 editions published between 1974 and 1975 in English and Undetermined and held by 4 WorldCat member libraries worldwide
This paper is an initial progress report on the development of an interactive system for verifying that computer programs meet given formal specifications. The system is based on the conventional inductive assertion method: given a program and its specifications, the object is to generate the verification conditions, simplify them, and prove what remains. This system addresses two aspects of software improvement of extreme importance to the military: increase in the quality of software and decrease in the cost of producing highquality software. A general description is given of the overall design philosophy, structure, and functional components of the system, and a simple sorting program is used to illustrate both the behavior of major system components and the type of user interaction the system provides
A proof rule for Euclid procedures by
John Guttag(
Book
)
3 editions published in 1977 in English and held by 3 WorldCat member libraries worldwide
The proof rules of Euclid, like the axiomatization of Pascal, presents a single definition of the various features of the language being defined. Little effort is made to explain the proof rules or to compare them to alternatives. In this paper we take one of our more complex proof rules, the rule for procedure definition and call, and attempt both to explain its workings and to compare it to two alternative rules. The rules we have chosen for comparison are Hoare's adaptation rule, from which our rule is derived, and the Pascal procedurecall rule. (Author)
3 editions published in 1977 in English and held by 3 WorldCat member libraries worldwide
The proof rules of Euclid, like the axiomatization of Pascal, presents a single definition of the various features of the language being defined. Little effort is made to explain the proof rules or to compare them to alternatives. In this paper we take one of our more complex proof rules, the rule for procedure definition and call, and attempt both to explain its workings and to compare it to two alternative rules. The rules we have chosen for comparison are Hoare's adaptation rule, from which our rule is derived, and the Pascal procedurecall rule. (Author)
An Informal Definition of Alphard (Preliminary) by W. A Wulf(
Book
)
1 edition published in 1978 in English and held by 2 WorldCat member libraries worldwide
The Alphard language design has four major goals: (1) to support modern programming methodology, (2) to permit practical program verification, (3) to permit extremely efficient object code to be produced, and (4) to permit the programmer to control certain implementation decisions  such as the representation of data structures. Previous Alphard papers have explored aspects of these issues as they relate to particular language features; to facilitate these explorations these papers used a different syntax for the language. The present report is a complete informal definition of Alphard that both simplifies and unifies the language. (Author)
1 edition published in 1978 in English and held by 2 WorldCat member libraries worldwide
The Alphard language design has four major goals: (1) to support modern programming methodology, (2) to permit practical program verification, (3) to permit extremely efficient object code to be produced, and (4) to permit the programmer to control certain implementation decisions  such as the representation of data structures. Previous Alphard papers have explored aspects of these issues as they relate to particular language features; to facilitate these explorations these papers used a different syntax for the language. The present report is a complete informal definition of Alphard that both simplifies and unifies the language. (Author)
Experience with inductive assertions for proving programs correct by
Ralph L London(
Book
)
1 edition published in 1969 in English and held by 2 WorldCat member libraries worldwide
1 edition published in 1969 in English and held by 2 WorldCat member libraries worldwide
Bibliography on proving the correctness of computer programs by
Ralph L London(
Book
)
2 editions published between 1969 and 1970 in English and held by 2 WorldCat member libraries worldwide
2 editions published between 1969 and 1970 in English and held by 2 WorldCat member libraries worldwide
Automatic program verification by
Shirō Igarashi(
Book
)
2 editions published in 1973 in English and held by 2 WorldCat member libraries worldwide
Defining the semantics of programming languages by axioms and rules of inference yields a deduction system within which proofs may be given that programs satisfy specifications. The deduction system herein is shown to be consistent and also deductive complete with respect to Hoare's system. A subgoaler for the deductive system is described whose input is a significant subset of Pascal Programs plus inductive assertions. The output is a set of verification conditions or lemmas to be proved. Several nontrivial arithmetic and sorting programs have been shown to satisfy specifications by using an interactive theorem prover to automatically generate proofs of the verification conditions. Additional components for a more powerful verification system are under construction. (Author)
2 editions published in 1973 in English and held by 2 WorldCat member libraries worldwide
Defining the semantics of programming languages by axioms and rules of inference yields a deduction system within which proofs may be given that programs satisfy specifications. The deduction system herein is shown to be consistent and also deductive complete with respect to Hoare's system. A subgoaler for the deductive system is described whose input is a significant subset of Pascal Programs plus inductive assertions. The output is a set of verification conditions or lemmas to be proved. Several nontrivial arithmetic and sorting programs have been shown to satisfy specifications by using an interactive theorem prover to automatically generate proofs of the verification conditions. Additional components for a more powerful verification system are under construction. (Author)
Correctness of the ALGOL procedure ASKFORHAND by
Ralph L London(
Book
)
1 edition published in 1968 in English and held by 1 WorldCat member library worldwide
1 edition published in 1968 in English and held by 1 WorldCat member library worldwide
Proof of algorithms : a new kind of certification by
Ralph L London(
Book
)
1 edition published in 1969 in English and held by 1 WorldCat member library worldwide
1 edition published in 1969 in English and held by 1 WorldCat member library worldwide
Computer programs can be proved correct : draft copy by
Ralph L London(
Book
)
1 edition published in 1968 in English and held by 1 WorldCat member library worldwide
1 edition published in 1968 in English and held by 1 WorldCat member library worldwide
Proving programs correct : some techniques and examples by
Ralph L London(
Book
)
1 edition published in 1970 in English and held by 1 WorldCat member library worldwide
1 edition published in 1970 in English and held by 1 WorldCat member library worldwide
Interval arithmetic for the Burroughs B5500: four ALGOL procedures and proofs of their correctness by
Donald I Good(
Book
)
1 edition published in 1968 in English and held by 1 WorldCat member library worldwide
1 edition published in 1968 in English and held by 1 WorldCat member library worldwide
Proofs of algorithms for asymptotic series by
Ralph L London(
Book
)
1 edition published in 1969 in English and held by 1 WorldCat member library worldwide
1 edition published in 1969 in English and held by 1 WorldCat member library worldwide
A local procedure for error detection and data smoothing by
Donald I Good(
Book
)
1 edition published in 1974 in English and held by 0 WorldCat member libraries worldwide
1 edition published in 1974 in English and held by 0 WorldCat member libraries worldwide
An Informal Definition of Alphard(
Book
)
1 edition published in 1978 in Undetermined and held by 0 WorldCat member libraries worldwide
1 edition published in 1978 in Undetermined and held by 0 WorldCat member libraries worldwide
Report on the programming language Euclid by
Butler W Lampson(
Book
)
1 edition published in 1981 in Undetermined and held by 0 WorldCat member libraries worldwide
1 edition published in 1981 in Undetermined and held by 0 WorldCat member libraries worldwide
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Related Identities
 Shaw, Mary computer scientist Author
 Wulf, William Allan Author
 CarnegieMellon University Computer Science Department
 University of Wisconsin Computer Sciences Department
 Good, Donald I. Author
 UNIVERSITY OF SOUTHERN CALIFORNIA MARINA DEL REY INFORMATION SCIENCES INST
 Bledsoe, W. W.
 Wulf, W. A. Author
 Guttag, John Author
 STANFORD UNIV CALIF Dept. of COMPUTER SCIENCE
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