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_5, if x_5 were a janitor, then x_5 is a server. There is at least one x_5 for which x_5 is a janitor if and only if x_5 is a server.
There is at least one x_5 for which if x_5 were a janitor, then x_5 is a server can be inferred via the existential biconditional elimination rule. There is at least one x_5 for which if x_5 were a server, then x_5 is a janitor can be inferred via the existential biconditional elimination rule.