A theorem proving system has been programmed for automating mildly complex proofs by structural induction. One purpose was to prove properties of simple functional programs without loops or assignments. One can see the formal system as a generalization of number theory: the formal language is typed and the induction rule is valid for all types. Proofs are generated by working backward from the goal. The induction strategy splits into two parts: (1) the selection of induction variables, which is claimed to be linked to the useful generalization of terms to variables, and (2) the generation of induction subgoals, in particular, the selection and specialization of hypotheses. Other strategies include a fast simplification algorithm. The prover can cope with situations as complex as the definition and correctness proof of a simple compiling algorithm for expressions. Descriptive Terms Program proving, theorem proving, data type, structural induction, generalization, simplification.

interpreter for logic programs (Sterling & Shapiro, 1986)...................138 1 1. INTRODUCTION The most important outcome of AI research during the 70s was the general acceptance of the major role of knowledge in intelligent systems (Buchanan & Feigenbaum, 1982). Lenat and Feigenbaum (1989) call this belief the knowledge as power hypothesis and assert it as: "The knowledge principle (KP) A system exhibits intelligent understanding and action at a high level of competence primarily because of the specific knowledge that it can bring to bear: the concepts, facts, representations, methods, models, metaphors, and heuristics about its domain of endeavor." Or as Buchanan and Feigenbaum (Buchanan & Feigenbaum, 1982) put it, "the power of an intelligent program to perform its task well depends primarily on the quantity and quality of knowledge it has about that task." Thus, it is not surprising that the general attitude toward knowledge was a greedy one - grab as much knowledge as you ca...

. The so-called "Boyer-Moore Theorem Prover" (otherwise known as "Nqthm") has been used to perform a variety of verification tasks for two decades. We give an overview of both this system and an interactive enhancement of it, "Pc-Nqthm," from a number of perspectives. First we introduce the logic in which theorems are proved. Then we briefly describe the two mechanized theorem proving systems. Next, we present a simple but illustrative example in some detail in order to give an impression of how these systems may be used successfully. Finally, we give extremely short descriptions of a large number of applications of these systems, in order to give an idea of the breadth of their uses. This paper is intended as an informal introduction to systems that have been described in detail and similarly summarized in many other books and papers; no new results are reported here. Our intention here is merely to present Nqthm to a new audience. This research was supported in part by ONR Contract N...

An equational approach to the synthesis of functional and logic program is taken. In this context, the synthesis task involves nding executable equations such that the given speci cation holds in their standard model. Hence, to synthesize such programs, induction is necessary.We formulate procedures for inductiveproof,aswell as for program synthesis, using the framework of \ordered rewriting". We also propose heuristics for generalizing from a sequence of equational consequences. These heuristics handle cases where the deductive process alone is inadequate for coming up with a program. 1.

We briefly review a mechanical theorem-prover for a logic of recursive functions over finitely generated objects including the integers, ordered pairs, and symbols. The prover, known both as NQTHM and as the Boyer-Moore prover, contains a mechanized principle of induction and implementations of linear resolution, rewriting, and arithmetic decision procedures. We describe some applications of the prover, including a proof of the correct implementation of a higher level language on a microprocessor defined at the gate level. We also describe the ongoing project of recoding the entire prover as an applicative function within its own logic.

This paper advocates a programming methodology using message passing. Efficient programs are derived for fast exponentiation, merging ordered sequences, and path existence determination in a directed graph. The problems have been proposed by John Reynolds as interesting ones to investigate because they. illustrate significant issues in programming. The methodology advocated here is directed toward the production of programs that are intended to execute efficiently in a computing environment with many processors. The absence of the COTO construct does not seem to be constricting in any respect in the development of efficient programs using the programming methodology advocated here. The programming problems arising from use of the GOTO construct have become well known over the last decade. However, removal of the construct from traditional programming languages has been found by many to be constricting and to result in inefficient programs. A number of proposals have been advanced to allow the construct in a restricted way e.g. Knuth: 1974 and Reynolds: 19771.