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: u_3 -> t. r_8 -> u_3. ~p. p <-> u_3. t -> r_8.
u_3 -> r_8 can be inferred via the transitivity rule. r_8 -> t can be inferred via the transitivity rule. t -> u_3 can be inferred via the transitivity rule. p -> u_3 can be inferred via the biconditional elimination rule. u_3 -> p can be inferred via the biconditional elimination rule. ~u_3 can be inferred via the biconditional elimination rule.