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: ~U(a). forall z: S(z) <-> U(z). q_3 <-> q. S(a) <-> q_3.
q_3 -> q can be inferred via the biconditional elimination rule. S(a) -> q_3 can be inferred via the biconditional elimination rule. q -> q_3 can be inferred via the biconditional elimination rule. q_3 -> S(a) can be inferred via the biconditional elimination rule. forall z: S(z) -> U(z) can be inferred via the universal biconditional elimination rule. forall z: U(z) -> S(z) can be inferred via the universal biconditional elimination rule.