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: q_1. ~s -> w. ~q_19. s <-> q_19.
q_1 and ~q_19 can be inferred via the conjunction rule. ~q_19 and q_1 can be inferred via the conjunction rule. s -> q_19 can be inferred via the biconditional elimination rule. q_19 -> s can be inferred via the biconditional elimination rule. ~s can be inferred via the biconditional elimination rule.