One-sided zeros of subsets of the semigroup of binary relations

The one-sided zeros of the elements and of the subsets of the semigroup of all binary relations on an arbitrary nonempty set, are described. For a finite set of zeros, formulas are obtained for their number.Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 42, No. 5, pp. 600–604, May, 1990.