WorldCat Identities

London, Ralph L.

Overview
Works: 25 works in 42 publications in 1 language and 56 library holdings
Roles: Author
Classifications: HF5548.5.A4, 510.785
Publication Timeline
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Most widely held works by Ralph L London
Abstraction and verification in Alphard : a symbol table example by Ralph L London( Book )
5 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 programmer-defined 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 )
3 editions published in 1976 in English and held by 7 WorldCat member libraries worldwide
Abstraction and verification in Alphard : introduction to language and methodology by William Allan Wulf( Book )
4 editions published in 1976 in English and held by 7 WorldCat member libraries worldwide
Alphard is a programming language whose goals include supporting both the development of well-structured 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 )
4 editions published in 1971 in English and Undetermined and held by 5 WorldCat member libraries worldwide
Using mainly structural induction, proofs of correctness of each of two running Lisp compilers for the PDP-10 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)
An Interactive Program Verification System by Donald I Good( Book )
3 editions published in 1974 in English 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 high-quality 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
Automatic program verification 1 a logical basis and its implementation by ShirĊ Igarashi( Book )
2 editions published in 1973 in English and held by 3 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 non-trivial 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)
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 procedure-call rule. (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
A computer program for discovering and proving sequential recognition rules for well-formed formulas defined by a Backus normal form grammar by Ralph L London( Book )
1 edition published in 1964 in English and held by 2 WorldCat member libraries worldwide
Bibliography on proving the correctness of computer programs by Ralph L London( Book )
1 edition published in 1969 in English and held by 1 WorldCat member library worldwide
A computer program for discovering and proving sequential recognition rules for well-formed formulas defined by a backus normal form grammar ( Book )
1 edition published in 1964 in English and held by 1 WorldCat member library 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 counter-examples. 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 Informal Definition of Alphard (Preliminary) ( Book )
1 edition published in 1978 in English and held by 1 WorldCat member library 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)
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
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
A computer program for discovering and proving recognition rules for Backus Normal Form grammars by Ralph L London( Book )
1 edition published in 1964 in English and held by 1 WorldCat member library worldwide
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
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
Abstraction and Verification in Alphard: Iteration and Generators ( Book )
1 edition published in 1976 in English and held by 1 WorldCat member library 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)
Bibliography on proving the correctness of computer programs : addition no. 1 by Ralph L London( Book )
1 edition published in 1970 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 1 WorldCat member library worldwide
 
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Languages
English (36)