[comp.theory] words problem in commutative semi-groups

lescanne@loria.crin.FR (Pierre Lescanne) (07/21/90)

Can someone give me pointers to the resolution of the word problem in
commutative semi-groups?


----- Pierre Lescanne -----

boykett@wacsvax.cs.uwa.OZ.AU (Tim Boykett) (07/25/90)

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.