Abstract

Formal proofs generated by mechanised theorem proving systems may consist of a large number of inferences. As these theorem proving systems are usually very complex, it is extremely difficult if not impossible to formally verify them. This calls for an independent means of ensuring the consistency of mechanically generated proofs. This paper describes a method of recording HOL proofs in terms of a sequence of applications of inference rules. The recorded proofs can then be checked by an independent proof checker. Also described in this paper is an efficient proof checker which is able to check a practical proof consisting of thousands of inference steps. 1 Introduction Formal methods have been used in the development of many safety-critical systems in the form of formal specification and formal proof of correctness. Formal proofs are usually carried out using theorem provers or proof assistants. These systems are based on well-founded formal logic, and provide a programming environmen...

Citations

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