Idempotent Elements of the Semigroups BX(D) Defined by Semilattices of the Class Σ2(X, 8), When Z7∩Z6 = Ø

By the symbol Ʃ_2(X, 8) we denote the class of all X- semilattices of unions whose every element is isomor¬phic to an X- semi¬lattice of form D = {Z_7, Z_6, Z_5, Z_4, Z_3, Z_2, Z_1, D}, where The paper gives description of idempotent elements of the semigroup B_X(D) which are defined by semilattices of the class Ʃ_2(X, 8), for which intersection the minimal elements is empty. When X is a finite set, the formulas are derived, by means of which the number of idempotent elements of the semigroup is calculated.