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: q -> W(a_17). U(a_17) <-> q. forall x_4: W(x_4) -> U(x_4).
U(a_17) -> q can be inferred via the biconditional elimination rule. q -> U(a_17) can be inferred via the biconditional elimination rule.