Abstract

This note briefly discusses how some of the ideas developed in the theory of coalgebras are used in a front-end tool called LOOP, developed jointly in Dresden and Nijmegen, for reasoning (with a back-end theorem prover) about classes in objectoriented languages. It will describe reasoning both about object-oriented specifications and about JAVA implementations, via examples. 1 Introduction One of the key aspects of object-orientation is that objects, as instances of a class, have a private state, which can only be accessed and modified via the operations (usually called attributes and methods) of the class of the object. It is precisely this aspect which forms the starting point of the coalgebraic analysis of classes and objects in an object-oriented setting, see [10,5]: a class is seen as a coalgebra, and an object of a class as an element of the state space of the coalgebra. More precisely, a coalgebra is an operation of the form c: X ! T (X), where X is the carrier set (or state sp...

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