meaning of the symbol $Z_n^*$ in discrete mathematics I was reading discrete Mathematics, and i found a symbol $$Z_n^*.$$ I don't know what it means.
The text says that the "image" with the multiplication operator is an abelian group.
can any one explain.
maybe the author is talking about the group of unit elements of $\mathbb{Z}_n$ ?
it means modulo n i.e after doing binary operation on a,b dividing the ans by n, then remainder is d final ans