During the last three decades several different styles of semantics for program ming languages have been developed. This book compares two of them: the operational and the denotational approach. On the basis of several exam ples we show how to define operational and denotational semantic models for programming languages. Furthermore, we introduce a general technique for comparing various semantic models for a given language. We focus on different degrees of nondeterminism in programming lan guages. Nondeterminism arises naturally in concurrent languages. It is also an important concept in...