Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!samsung!rex!ames!uhccux!virtue!comp.vuw.ac.nz!munnari.oz.au!uniwa!wacsvax!boykett From: boykett@wacsvax.cs.uwa.OZ.AU (Tim Boykett) Newsgroups: comp.theory Subject: Re: words problem in commutative semi-groups Message-ID: Date: 25 Jul 90 06:17:41 GMT References: <9007201700.AA16081@loria.crin.fr> Organization: Computer Science,The University of Western Australia. Lines: 22 In <9007201700.AA16081@loria.crin.fr> lescanne@loria.crin.FR (Pierre Lescanne) writes: >Can someone give me pointers to the resolution of the word problem in >commutative semi-groups? >----- Pierre Lescanne ----- Pardon me if this is ignorant, but given the comm sgp generated by ai, i in I, some index set, cannot any word in the comm sgp be written x y z q a1 a2 a3 a4 ... or somesuch. ( ie there is a map from I(1,2,3 etc) to the positive integers (x y z q ..), ie the exponents). To get this map, or list of exponents, we need only count occurences of each ai. This hasn't been explained very well, I'm supposed to be doing something else :-) Tim.