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: t <-> r_1. ~t -> w. forall x_9: P_9(x_9). ~r_1.
t -> r_1 can be inferred via the biconditional elimination rule. r_1 -> t can be inferred via the biconditional elimination rule. ~t can be inferred via the biconditional elimination rule.