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_2, x_2 will go running if and only if x_2 is a janitor. There is at least one x_2 for which x_2 is not a janitor.
For all x_2, if x_2 goes running, then x_2 is a janitor can be inferred via the universal biconditional elimination rule. For all x_2, if x_2 were a janitor, then x_2 is running can be inferred via the universal biconditional elimination rule. There is at least one x_2 for which x_2 will not go running can be inferred via the existential biconditional elimination rule.