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_14, x_14 will sleep if and only if x_14 will work. If Sarah were a nurse, then Richard is sleeping. If Richard works, then Sarah is a nurse.
If Richard works, then Richard is sleeping can be inferred via the transitivity rule. For all x_14, if x_14 sleeps, then x_14 is working can be inferred via the universal biconditional elimination rule. For all x_14, if x_14 works, then x_14 is sleeping can be inferred via the universal biconditional elimination rule.