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: ~q_1. forall x_15: S(x_15) -> S_15(x_15). S_15(a_15) -> u. u -> q_1.
~u can be inferred via the modus tollens rule. S_15(a_15) -> q_1 can be inferred via the transitivity rule.