NESTED GUARDED HORN CLAUSES

作     者：MORENO FALASCHI MAURIZIO GABBRIELLI GIORGIO LEVI MASAKI MURAKAMI 

作者机构：Dipartimento di Informatica Università di Pisa Corso Italia 40 56125 Pisa Italy Institute for New Generation Computer Technology 4–28 Mita-1 Minato-ku Tokyo 108 Japan Current address: Fujitsu Ltd. International Institute for Advanced Study of Social Information Science 17–25 Shinkamata 1-chome Ota-ku Tokyo 144 Japan. 

出 版 物：《International Journal of Foundations of Computer Science》 

年 卷 期：1990年第1卷第3期

页      面：249-263页

学科分类：08[工学] 0812[工学-计算机科学与技术（可授工学、理学学位）] 

主　　题：Concurrent logic programming Semantics Unfolding 

摘      要：This paper defines a new concurrent logic language, Nested Guarded Horn Clauses (NGHC). The main new feature of the language is its concept of guard. In fact, an NGHC clause has several layers of (standard) guards. This syntactic innovation allows the definition of a complete (i.e. always applicable) set of unfolding rules and therefore of an unfolding semantics which is equivalent, with respect to the success set, to the operational semantics. A fixpoint semantics is also defined in the classic logic programming style and is proved equivalent to the unfolding one. Since it is possible to embed Flat GHC into NGHC, our method can be used to give a fixpoint semantics to FGHC as well.