ylfink@water.UUCP (11/10/87)
DEPARTMENT OF COMPUTER SCIENCE UNIVERSITY OF WATERLOO SEMINAR ACTIVITIES FORMAL LANGUAGE THEORY SEMINAR - Thursday, November 12, 1987 Dr. Jacques Sakarovitch, of the Laboratoire Informatique Theorique et Programmation, Paris, France, will speak on ``On Regular Trace Languages (And Other Stories)''. TIME: 3:30 PM ROOM: MC 6082 ABSTRACT The starting point of the work that will be reported in the seminar is the characterization of commutation relations with the property that the corresponding regular trace languages are closed under complementation or are unambiguous. This will be established as a consequence of a property of free products (of monoids). This property, in turn, will be proved by means of a generalization of finite automata (that has been more or less folklore up to now) and that gives new insights on several classical results, as Chomsky normal form for context-free grammars.