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