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_3 -> r. r_3 <-> w_3. ~u_3. u_3 <-> r.
r_3 -> w_3 can be inferred via the biconditional elimination rule. u_3 -> r can be inferred via the biconditional elimination rule. w_3 -> r_3 can be inferred via the biconditional elimination rule. r -> u_3 can be inferred via the biconditional elimination rule. ~r can be inferred via the biconditional elimination rule.