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: ~p_1. p_1 <-> t_2. u_3 and r.
u_3 can be inferred via the simplification rule. r can be inferred via the simplification rule. p_1 -> t_2 can be inferred via the biconditional elimination rule. t_2 -> p_1 can be inferred via the biconditional elimination rule. ~t_2 can be inferred via the biconditional elimination rule.