Title: An answer to A.D.Wallace’s question about countably compact cancellative semigroups
Abstract: It is shown under CH that there exists a countably compact topological semigroup with two-sided cancellation which is not a topological group. “Wallace’s question” of 40 years standing is thus settled in the negative unless CH is explicitly denied. The example is a topological subsemigroup of an uncountable product of circle groups.