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: John is playing tennis. For all y_2, y_2 is a politician and y_2 will listen to a song. If John plays tennis, then Richard is taking a plane.
Richard is taking a plane can be inferred via the modus ponens rule. For all y_2, y_2 is a politician can be inferred via the universal simplification rule. For all y_2, y_2 will listen to a song can be inferred via the universal simplification rule.