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: ~t. t -> u_1. t <-> u_1. w.
~t and w can be inferred via the conjunction rule. w and ~t can be inferred via the conjunction rule. t -> u_1 can be inferred via the biconditional elimination rule. u_1 -> t can be inferred via the biconditional elimination rule. ~u_1 can be inferred via the biconditional elimination rule.