Consider the following premises. R_7(e) <-> r_2. forall x_7: R_7(x_7) <-> S_7(x_7). ~S_7(e). Can we infer r_2 from them?
 From forall x_7: R_7(x_7) <-> S_7(x_7) we can infer R_7(e) <-> S_7(e). From R_7(e) <-> S_7(e), ~S_7(e) we can infer ~R_7(e). Finally, from R_7(e) <-> r_2, ~R_7(e) we can infer ~r_2, which contradicts r_2. Therefore, the answer is no.