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_8 <-> u. ~u. s_2 -> p_8.
p_8 -> u can be inferred via the biconditional elimination rule. u -> p_8 can be inferred via the biconditional elimination rule. ~p_8 can be inferred via the biconditional elimination rule.