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, if x_7 were a janitor, then x_7 is not running. For all x_7, x_7 will go running and x_7 is a writer. For all x_7, x_7 is a soldier if and only if x_7 is a janitor.
For all x_7, x_7 will go running can be inferred via the universal simplification rule. For all x_7, x_7 is a writer can be inferred via the universal simplification rule. For all x_7, if x_7 were a soldier, then x_7 is a janitor can be inferred via the universal biconditional elimination rule. For all x_7, if x_7 were a janitor, then x_7 is a soldier can be inferred via the universal biconditional elimination rule.