Abstract: The article defines algebraic semantics of singular (call-time-choice) and plural (run-time-choice) nondeterministic parameter passing and presents a specification language in which operations with both kinds of parameters simultaneously can be defined. Sound and complete calculi for both semantics are introduced. We study the relations between the two semantics and point out that axioms for operations with plural arguments may be considered as axiom schemata for operations with singular arguments.
Keywords: algebraic specification, many-sorted algebra, nondeterminism, sequent calculus.
AMS classifications: 68Q65, 68Q60, 68Q10, 68Q55, 03B60, 08A70.