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: ~s. r_3 -> s_1. w_2 -> s_1. t <-> s. r_3 or w_2.
s_1 can be inferred via the disjunction elimination rule. t -> s can be inferred via the biconditional elimination rule. s -> t can be inferred via the biconditional elimination rule. ~t can be inferred via the biconditional elimination rule.