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. t or ~s_2. p -> w_1. w_1 <-> s_2.
~s_2 can be inferred via the disjunctive syllogism rule. s_2 -> t can be inferred via the rewriting rule. w_1 -> s_2 can be inferred via the biconditional elimination rule. s_2 -> w_1 can be inferred via the biconditional elimination rule.