Consider the following premises. forall y: P_1(y) <-> Q(y). forall y: U_4(y) <-> T(y). forall y: T(y) <-> Q(y). exists y: ~U_4(y). Can we infer forall y: P_1(y) from them?
 From forall y: U_4(y) <-> T(y), exists y: ~U_4(y) we can infer exists y: ~T(y). From forall y: T(y) <-> Q(y), exists y: ~T(y) we can infer exists y: ~Q(y). Finally, from forall y: P_1(y) <-> Q(y), exists y: ~Q(y) we can infer exists y: ~P_1(y), which contradicts forall y: P_1(y). Therefore, the answer is no.