Final data type specifications: a new data type specification method

A new specification method for data types is presented, which is distinguished by the semantic objects it specifies. In particular, only final data types [GGM,W] are specifiable. A final data type is one in which no two elements are "input-output equivalent". It is argued that the mathematical properties of final data types characterize abstractness on the semantic level.Examples are given to show that final data type specifications are easy to construct and use.