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_7 or q_1. u_2 <-> t. ~t. p_7 or u_2.
u_2 or q_1 can be inferred via the resolution rule. u_2 -> t can be inferred via the biconditional elimination rule. t -> u_2 can be inferred via the biconditional elimination rule. ~u_2 can be inferred via the biconditional elimination rule.