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: Charles is driving a car if and only if it is sunny. If it is cold, then Charles is driving a car. It is cold or Robert is not playing squash.
If Robert plays squash, then it is cold can be inferred via the rewriting rule. If Charles drives a car, then it is sunny can be inferred via the biconditional elimination rule. If it is sunny, then Charles is driving a car can be inferred via the biconditional elimination rule.