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. p_11 -> r_3. p_11 <-> r.
p_11 -> r can be inferred via the transitivity rule. p_11 -> r can be inferred via the biconditional elimination rule. r -> p_11 can be inferred via the biconditional elimination rule.