Designs D_1 = (P_1, B_1, I_1) and D_2 = (P_2, B_2, I_2) are identical if P_1 = P_2, B_1 = B_2 and I_1 = I_2.

D eq E : Inc, Inc -> BoolElt

True if the incidence structures D and E are identical, otherwise false.

True if the incidence structures D and E are not identical, otherwise false.

True if the incidence structures D and E are isomorphic, otherwise false. If they are isomorphic, then an isomorphism is returned as the second value.