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_18, x_18 is a sailor. It is snowing or it is raining. If it rains, then Patricia is excited. It is snowing if and only if Patricia is excited.
If it snows, then Patricia is excited can be inferred via the biconditional elimination rule. If Patricia were excited, then it is snowing can be inferred via the biconditional elimination rule.