ON DECOMPOSITIONS OF REGULAR EVENTS

被引:14
作者
BRZOZOWSKI, JA
COHEN, R
机构
[1] University of Waterloo, Department of Applied Analysis and Computer Science, Waterloo, Ontario, Canada
关键词
D O I
10.1145/321495.321505
中图分类号
TP3 [计算技术、计算机技术];
学科分类号
0812 ;
摘要
Decompositions of regular events into star events, i.e. events of the form W = V*, are studied. Mathematically, the structure of a star event is that of a monoid. First it is shown that every regular event contains a finite number of maximal star events, which are shown to be regular and can be effectively computed. Necessary and sufficient conditions for a regular event to be the union of its maximal star events are found. Next, star events are factored out from arbitrary events, yielding the form W - V*T. For each W there exists a unique largest V* and a unique smallest T; an algorithm for finding suitable regular expressions for V and T is developed. Finally, an open problem of Paz and Peleg is answered: Every regular event is decomposable as a finite product of star events and prime events. © 1969, ACM. All rights reserved.
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页码:132 / +
页数:1
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