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_2. p <-> q. q <-> s_2.
p -> q can be inferred via the biconditional elimination rule. q -> s_2 can be inferred via the biconditional elimination rule. q -> p can be inferred via the biconditional elimination rule. s_2 -> q can be inferred via the biconditional elimination rule. ~q can be inferred via the biconditional elimination rule.