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_9, x_9 will play tennis. It is not raining. John is excited if and only if it is raining. If John were not excited, then it is windy.
If John were excited, then it is raining can be inferred via the biconditional elimination rule. If it rains, then John is excited can be inferred via the biconditional elimination rule. John is not excited can be inferred via the biconditional elimination rule.