Rina S. Cohen

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An co-language is a set consis t ing of oJ-length s t r ings over some alphabet; an o)-automaton is a device capable of recognizing oMength i npu t tapes. T h i s paper in t roduces the basic not ions concern ing genera t ion of ~o-languages by m e a n s of oJ-grammars and their recognition by oJ-automata wi th var ious recognit ion modes . At ten t ion is(More)
This paper deals with restricted star height of regular sets, as defined by L. C. Eggan. Theorems relating the star height of a regular event with the structure of the reduced deterministic automaton recognizing the event are presented. These theorems provide new techniques for establishing star height; in many cases the exact star height of the given(More)
Decompositions of regular events into star events, i.e. events of the form <italic>W</italic> = <italic>V</italic>*, 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.(More)