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: If William were a janitor, then William is a scientist. For all x, x is a scientist if and only if x is a janitor.
For all x, if x were a scientist, then x is a janitor can be inferred via the universal biconditional elimination rule. For all x, if x were a janitor, then x is a scientist can be inferred via the universal biconditional elimination rule.