Extension of a family maximal free submonoids of the semigroup X
Liping Wang · Journal of Guizhou Normal University · 2011
LetX* be the free monoid generated by an alphabet X,{B1,B2}be an arbitrary two-partition on X,and A=B2∪E,where E=B1XN(B02B1∪B2B1∪B22B1∪…∪BM-12B1∪BM2X),N≥0,M≥0.In [1],monoidA* are shown to be maximal free submonoids of the free monoid,where N=0.In this paper,we have showed that monoidA* are also maximal free submonoids of the monoid X*,where N≥2.