Algebraic-coalgebraic specification in CoCASL

Abstract

We introduce CoCASL as a simple coalgebraic extension of the algebraic specification language CASL. CoCASL allows the nested combination of algebraic datatypes and coalgebraic process types. We show that the well-known coalgebraic modal logic can be expressed in CoCASL. We present sufficient criteria for the existence of cofree models, also for several variants of nested cofree and free specifications. Moreover, we describe an extension of the existing proof support for CASL (in the shape of an encoding into higher-order logic) to CoCASL. © Springer-Verlag Berlin Heidelberg 2003.