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 x_7, x_7 will play squash. There is at least one x_7 for which if x_7 takes a plane, then x_7 is not playing squash. For all x_7, x_7 will take a plane or x_7 is not fast.
There is at least one x_7 for which x_7 will not take a plane can be inferred via the existential modus tollens rule. For all x_7, if x_7 were fast, then x_7 is taking a plane can be inferred via the universal rewriting rule.