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: r -> w. p or r. p -> w. w -> r.
p -> r can be inferred via the transitivity rule. w can be inferred via the disjunction elimination rule. r <-> w can be inferred via the biconditional introduction rule. w <-> r can be inferred via the biconditional introduction rule.