Abstract

We present an approach to nondeterministic time based on a concept of nondeterministic world. A nondeterministic world is a set of some equipos- sible states. Such a world is not treated as whole, it is neither atomic nor indivisible. Given a world representing the present, the past worlds are its subsets and the future worlds are sets in which it is contained. Thus we assume that worlds involve change and the way they change is expansion. In our approach indeterminism occurs in the two levels. First, we admit nondeterministic worlds, consisting of possibly many instances. Second, we treat the future as nondeterministically reachable. As a consequence, for any world there are many past worlds from which the world might be reached and many future worlds which might be reached from the world