SEMIGROUP FORUM, cilt.78, sa.3, ss.528-535, 2009 (SCI-Expanded)
In this paper we study dense inverse subsemigroups of topological inverse semigroups. We construct a topological inverse semigroup from a semilattice. Finally, we give two examples of the closure of B((-infinity, infinity))(1), a topological inverse semigroup obtained by starting with the real numbers as a semilattice with the operation a boolean OR b = sup{a, b}.