Right-topological semigroup operations on inclusion hyperspaces
  We show that for any discrete semigroup $X$ the semigroup operation can be extended to a right-topological semigroup operation on the space $G(X)$ of inclusion hyperspaces on $X$. We detect some important subsemigroups of $G(X)$, study the minimal ideal, the (topological) center, left cancelable elements of $G(X)$, and describe the structure of the semigroups $G(\IZ_n)$ for small numbers $n$. 
Volodymyr Gavrylkiv