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 or ~p. p_8 -> p. u <-> p_8.
p -> u can be inferred via the rewriting rule. u -> p_8 can be inferred via the biconditional elimination rule. p_8 -> u can be inferred via the biconditional elimination rule.