Abstract

The main result of the paper is a constructive proof of the following equivalence: two pure λ-terms are observationally equivalent in the lazy concurrent λ-calculus iff they have the same Lévy-Longo trees. An algorithm which allows to build a context discriminating any two pure λ-terms with different Lévy-Longo trees is described. It follows that contextual equivalence coincides with behavioural equivalence (bisimulation) as considered by Sangiorgi. Another consequence is that the discriminating power of concurrent lambda contexts is the same as that of Boudol-Laneve's contexts with multiplicities.

Citations