What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Name the inference rule being used: W(a_15) <-> Q(a_20). forall x_3: P_1(x_3) -> Q(x_3). forall x_15: W(x_15) -> S_15(x_15). ~S_15(a_15).
W(a_15) -> Q(a_20) can be inferred via the biconditional elimination rule. Q(a_20) -> W(a_15) can be inferred via the biconditional elimination rule.