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. t -> q_19. ~q_19. q_19 -> t. p -> t.
~t can be inferred via the modus tollens rule. q and ~q_19 can be inferred via the conjunction rule. ~q_19 and q can be inferred via the conjunction rule. t <-> q_19 can be inferred via the biconditional introduction rule. q_19 <-> t can be inferred via the biconditional introduction rule.