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: p <-> r_4. ~r_4. p <-> t.
p -> r_4 can be inferred via the biconditional elimination rule. p -> t can be inferred via the biconditional elimination rule. r_4 -> p can be inferred via the biconditional elimination rule. t -> p can be inferred via the biconditional elimination rule. ~p can be inferred via the biconditional elimination rule.