Consider the following premises. p <-> S_21(a_21). r_3 <-> p. forall x_21: R_21(x_21) <-> S_21(x_21). ~R_21(a_21). Can we infer r_3 from them?
 From forall x_21: R_21(x_21) <-> S_21(x_21) we can infer R_21(a_21) <-> S_21(a_21). From R_21(a_21) <-> S_21(a_21), ~R_21(a_21) we can infer ~S_21(a_21). From p <-> S_21(a_21), ~S_21(a_21) we can infer ~p. Finally, from r_3 <-> p, ~p we can infer ~r_3, which contradicts r_3. Therefore, the answer is no.