Blended Algebraic and Denotational
		     Semantics for ADT Languages
			 with Mutable Objects

				  by
	      Gary T. Leavens and Krishna Kishore Dhara
				   
			       Abstract

This paper presents a semantics for a simple language that is a blend
of algebraic models and traditional denotational semantics.  In this
semantics, implementations of user-defined abstract data types are
``compiled'' into an algebraic structure, which is used by the
denotational part of the semantics whenever an operation of the data
type is invoked.  To show the utility of such a semantics, an
algebraic characterization of simulation between states over such
algebras is given, and it is shown that simulation is preserved by
expressions and commands in the language.


(Note: versions TR93-21 and TR93-21a were titled: "A Model Theory for
Abstract Data Types with Mutable Objects (extended abstract)".)