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 <-> p. w or p. s_1 -> t. w -> s_1.
w -> t can be inferred via the transitivity rule. t -> p can be inferred via the biconditional elimination rule. p -> t can be inferred via the biconditional elimination rule.