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: Elisabeth is sleeping if and only if it is windy. It is windy. If Mary reads a book, then Elisabeth is not sleeping.
If Elisabeth sleeps, then it is windy can be inferred via the biconditional elimination rule. If it is windy, then Elisabeth is sleeping can be inferred via the biconditional elimination rule.