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: For all y, if y were happy, then y is taking a plane. For all y, if y plays a game, then y is happy. There is at least one y for which y will not take a plane.
There is at least one y for which y is not happy can be inferred via the existential modus tollens rule. For all y, if y plays a game, then y is taking a plane can be inferred via the universal transitivity rule.