Natural Semantics

During the past few years, many researchers have begun to present semantic specifications in a style that has been strongly advocated by Plotkin in [19]. The purpose of this paper is to introduce in an intuitive manner the essential ideas of the method that we call now Natural Semantics~ together with its connections to ideas in logic and computing. Natural Semantics is of interest per se and because it is used as a semantics specification formalism for an interactive computer system that we are currently building at INRIA.