A complete characterization of hyperidentities of the variety of weakly idempotent lattices

A hyperidentity is a second order universal formula, i.e., a universal formula from the second order language (in the sense of A. Church and A.I. Mal´tsev). The hyperidentities of the variety of weakly idempotent lattices are completely characterized in this paper. The existence of a finite base of hyperidentities for this variety is proved as a consequence.