1 research outputs found

    Computational and structural aspects of openly specified type hierarchies

    No full text
    Abstract. One may identify two main approaches to the description of type hierarchies. In total specification, a unique hierarchy is described. In open specification, a set of constraints identifies properties of the hierarchy, without providing a complete description. Open specification provides increased expressive power, but at the expense of considerable computational complexity, with essential tasks being NP-complete or NP-hard. In this work, a formal study of the structural and computational aspects of open specification is conducted, so that a better understanding of how techniques may be developed to address these complexities. In addition, a technique is presented, based upon Horn clauses, which allows one to obtain answers to certain types of queries on open specifications very efficiently. 1
    corecore