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_4. t -> s. t <-> q_4. r_2 -> t. s -> r_2.
t -> r_2 can be inferred via the transitivity rule. r_2 -> s can be inferred via the transitivity rule. s -> t can be inferred via the transitivity rule. t -> q_4 can be inferred via the biconditional elimination rule. q_4 -> t can be inferred via the biconditional elimination rule. ~t can be inferred via the biconditional elimination rule.