A set A and an integer n > 1
are given. S is any family of subsets of An. Necessary and sufficient conditions are
found for the existence of a set F of finitary partial operations on A such that S is
the set of all subalgebras of ⟨A;F⟩n. As a corollary, a family E of equivalence
relations on A is the set of all congruences on ⟨A;F⟩ for some F if and only if E is an
algebraic closure system on A2.