Two goals, simplicity of program designing, and efficiency of its computation, al- ways remain topical in programming, and more than anything this is true about parallel programming systems. The former goal is usually achieved for declar- ative programming languages, the latter - by embedding of coordination level operators. One of the earliest such extensions, future annotation, isa proposed in [3]. Their use allows to start a function computation before the moment when computation of its annotated arguments will be completed. Another advance to increase program parallelization was using of nondeterministic operators in pseudo-functional languages [5]. One more resource widely used in logic pro- gramming to program parallelization is speculative computation of alternative branches.