The respects relation can be used to characterize the information that remains unchanged during type conversions. This basic research paper presents a formal definition of this relation. The definition is based on the Liskov and Wing behavioral notion of subtyping. The authors also show how respects can be applied in the Typed Object Model Conversion Service. Moreover, an extension of respects for concrete types and its application to type evolution and reusability are discussed.

The importance of this work is mainly theoretical. The material is of interest to people doing basic research on programming languages, compilers, formal languages, object-oriented methodologies, and related areas. Secondarily, the respects relation could be used during the design and evolution of a type conversion system as a theoretical framework to be fulfilled by the type converters.

Although the subject is theoretical, the presentation is good and well structured, and the bibliography is adequate. Overall, this paper is good. The ideas presented could prove useful in interoperability and reusability issues and for future programming methodologies. The reader should have a basic familiarity with programming language theory and object-oriented methodologies and an adequate mathematical background.