We show that the technique to prove equivalence of operational and denotational cpo based semantics using retractions, as introduced in de Bruin & Vink [1989] for a sequential backtracking language, can be applied to parallel languages as well. We prove equivalence for a uniform language in which procedure calls need not be guarded. The unguardedness is taken care of by giving a semantics in which the nondeterminism is demonic.

sequential backtracking language, uniform language
Erasmus School of Economics

de Bruin, A, & de Vink, E.P. (1990). Denotational semantics for unguarded recursion: the demonic case. Retrieved from http://hdl.handle.net/1765/1502