Hi,

I have the following problem: I have a semigroup H inside a free group G.
G is of finite rank but clearly infinite. H is given by some generators,
but they could be redundant or have some relations. I would like to know
the relations between these generators in the semigroup H, or at least to
know which generators are necessary to get H. Is this possible in some
way?

Thank you very much,

Cinzia