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 cloudy if and only if it is cold. If David were a poet, then it is cold. It is overcast or it is not cloudy.
If it is cloudy, then it is overcast can be inferred via the rewriting rule. If it is cloudy, then it is cold can be inferred via the biconditional elimination rule. If it is cold, then it is cloudy can be inferred via the biconditional elimination rule.