Unifying ADT - and Evolving Algebra Specifications

It is the aim of this paper to demonstrate that the notion of Di-algebras, introduced by T. Hagino, may be used to unify algebraic speciications of ADT's with the basic ideas of evolving algebras (E{algebras for short) which use static algebras as states of dynamic systems. The resulting speciication formalism is based on initial and terminal constraints of quasi varieties of Di{algebras. Initial constraints deene abstract data types and terminal constraints deene types of behaviors of abstract machines. The layered use of initial and terminal constraints leads to speciications of systems.