Walter G. Olthoff

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This thesis develops a semantic model of inheritance and investigates its applications for the analysis and design of programming languages. Inheritance is a mechanism for incre-mental programming in the presence of self-reference. This interpretation of inheritance is formalized using traditional techniques of fixed-point theory, resulting in a(More)
Bounded quantification was introduced by Cardelli and Wegner as a means of typing functions that operate uniformly over all subtypes of a given type. They defined a simple " object " model and used bounded quantifica-tion to type-check functions that make sense on all objects having a specified set of " attributes. " A more realistic presentation of(More)
This paper develops a system of explicit interfaces for object-oriented programming. The system provides the benefits of module interfaces found in languages like Ada and Modula-2 while preserving the expressiveness that gives untyped object-oriented languages like Smalltalk their flexibility. Interfaces are interpreted as polymorphic types to make the(More)
Object-oriented programming and abstract data type (ADT) theory have emerged from the same origin of computer science: the inability to deal efficiently with 'programming in the large' during the early seventies. Each of the approaches has led to significant practical and theoretical results resp. Nevertheless it is still unsatisfactory that up to now the(More)
The APE (Automatic Programming Expert) system constructs executable and efficient programs from ■ algebraic specifications of abstract data types, and • abstract algorithms given as conditional term-rewrite-rule-systems with term', built up from operation symbols of the abstract data types involved. The APE is an experimental system devised to develop(More)
Founded in 1988, DFKI today is one of the largest nonprofit contract research institutes in the field of innovative software technology based on Artificial Intelligence (AI) methods. DFKI is focusing on the complete cycle of innovation — from world-class basic research and technology development through leading-edge demonstrators and prototypes to product(More)