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: If it is late, then it is snowing. It is not late. It is snowing or it is not overcast. If it snows, then it is late.
It is not snowing can be inferred via the modus tollens rule. If it is overcast, then it is snowing can be inferred via the rewriting rule. It is late if and only if it is snowing can be inferred via the biconditional introduction rule. It is snowing if and only if it is late can be inferred via the biconditional introduction rule.