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: p -> s. u_3 <-> t_3. t -> t_3. u_3. s -> ~t_3.
p -> ~t_3 can be inferred via the transitivity rule. u_3 -> t_3 can be inferred via the biconditional elimination rule. t_3 -> u_3 can be inferred via the biconditional elimination rule.