Let R(X) denote the set of all relations on a set X. Then R(X) becomes a semigroup under composition. The purpose of this paper is to describe the element of R(X) which is left cancellative and right cancellative.
Bulletin of Mathematical Sciences and Applications (Volume 2)
C. Namnak and R. Sanguanwong, "Left Cancellative and Right Cancellative Elements of Semigroup of Relations", Bulletin of Mathematical Sciences and Applications, Vol. 2, pp. 38-40, 2012