Deductive Software Verification

Abstract

In the late 1960’s, several researchers, in particular Floyd [45] and Hoare [63], advocated the idea of formally verifying algorithms and computer programs. The techniques developed involved formalisms that combine program text and logic, used within specially developed proof systems. Later works considered the addition of various programming constructs such as array variables and procedure calls [85] and concurrency [86, 108]. It was also suggested that such proof systems will be used in the opposite way: applying methods and tools related to deductive verification to develop provably correct programs from a given specification. A collection of powerful mechanized theorem provers have been developed recently (see a list of some of these tools at the end of this chapter). These can assist in obtaining correctness proofs and enforcing the correct use of deductive verification.

‘Please your Majesty,’ said the Knave, ‘I didn’t write it, and they can’t prove I did: there’s no name signed at the end.’

‘If you didn’t sign it,’ said the King, ‘that only makes the matter worse. You MUST have meant some mischief, or else you’d have signed your name like an honest man.’

‘That PROVES his guilt,’ said the Queen.

Lewis Carroll, Alice’s Adventures in Wonderland