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: forall y: ~W(y). u or ~W(b). W(b) <-> u.
W(b) -> u can be inferred via the rewriting rule. W(b) -> u can be inferred via the biconditional elimination rule. u -> W(b) can be inferred via the biconditional elimination rule.