Consider the following premises. forall x_15: ~R_15(x_15). p_4 <-> p. p <-> R_15(a_15). Can we infer ~p_4 from them?
 From forall x_15: ~R_15(x_15) we can infer ~R_15(a_15). From p <-> R_15(a_15), ~R_15(a_15) we can infer ~p. From p_4 <-> p we can infer p_4 -> p. Finally, from p_4 -> p, ~p we can infer ~p_4. Therefore, the answer is yes.