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 <-> p. u <-> q_7. ~p. q. s_3 -> ~q.
~s_3 can be inferred via the modus tollens rule. ~p and q can be inferred via the conjunction rule. q and ~p can be inferred via the conjunction rule. u -> p can be inferred via the biconditional elimination rule. u -> q_7 can be inferred via the biconditional elimination rule. p -> u can be inferred via the biconditional elimination rule. q_7 -> u can be inferred via the biconditional elimination rule. ~u can be inferred via the biconditional elimination rule.