In the past decade, semantical domains of programming languages have been modeled by c.p.o.‘s ([5,6]), i.e. partially ordered sets where every ascending chain has a least upper bound. As well important are chain-complete subsets of c.p.o.‘s which also have the “closed under chain” property. This paper is devoted to the study of chain-complete subsets of the lattice Pw, a universal domain for data types ([6,8]). A subset E of a c.p.0. is said to be chain-complete if it contains the least upper… CONTINUE READING