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: It is overcast. If it rains, then it is cloudy. If it rains, then it is not overcast. If it is cloudy, then it is raining.
It is not raining can be inferred via the modus tollens rule. If it is cloudy, then it is not overcast can be inferred via the transitivity rule. It is raining if and only if it is cloudy can be inferred via the biconditional introduction rule. It is cloudy if and only if it is raining can be inferred via the biconditional introduction rule.