Amir Pnueli

Specification and verification of concurrent programs by ∀-automata

∀-automata are non-deterministic finite-state automata over infinite sequences. They differ from conventional automata in that a sequence is accepted if all runs of the automaton over the sequence are accepting. These automata are suggested as a formalism for the specification and verification of temporal properties of concurrent programs. It is shown that they are as expressive as extended temporal logic (ETL), and, in some cases, provide a more compact representation of properties than temporal logic. A structured diagram notation is suggested for the graphical representation of these automata. A single sound and complete proof rule is presented for proving that all computations of a program have the property specified by a ∀-automaton.

Formalization of properties of recursively defined functions

This paper is concerned with the relationship between the convergence, correctness and equivalence of recursively defined functions and the satisfiability (or unsatisfiability) of certain first-order formulas.