What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? ~R_11(a_11) or r_7. p_15 <-> q_15. ~q_15. S_11(a_11) -> p_15. forall x_11: R_11(x_11) or S_11(x_11).
p_15 -> q_15. q_15 -> p_15. ~p_15.