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: s_3 -> s. s_3 <-> u. q. ~u. s -> s_3.
q and ~u can be inferred via the conjunction rule. ~u and q can be inferred via the conjunction rule. s_3 <-> s can be inferred via the biconditional introduction rule. s <-> s_3 can be inferred via the biconditional introduction rule. s_3 -> u can be inferred via the biconditional elimination rule. u -> s_3 can be inferred via the biconditional elimination rule. ~s_3 can be inferred via the biconditional elimination rule.