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 cold, then it is snowing. If it snows, then it is cold. It is snowing or it is not cold.
If it is cold, then it is snowing can be inferred via the rewriting rule. It is cold if and only if it is snowing can be inferred via the biconditional introduction rule. It is snowing if and only if it is cold can be inferred via the biconditional introduction rule.