Consider the following premises. r_4 -> R(j_2). ~R_4(j_2). ~r_4 -> u. forall z_1: R(z_1) <-> R_4(z_1). Can we infer u from them?
 From forall z_1: R(z_1) <-> R_4(z_1) we can infer R(j_2) <-> R_4(j_2). From R(j_2) <-> R_4(j_2), ~R_4(j_2) we can infer ~R(j_2). From r_4 -> R(j_2), ~R(j_2) we can infer ~r_4. Finally, from ~r_4 -> u, ~r_4 we can infer u. Therefore, the answer is yes.