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: It is cold. Elisabeth is a server if and only if Charles is a cashier. Elisabeth is a server or it is raining. If it rains, then Charles is a cashier.
If Elisabeth were a server, then Charles is a cashier can be inferred via the biconditional elimination rule. If Charles were a cashier, then Elisabeth is a server can be inferred via the biconditional elimination rule.