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 Jessica is cooking. If Jessica cooks, then it is late. Jessica is not cooking.
It is not late can be inferred via the modus tollens rule. It is late if and only if Jessica is cooking can be inferred via the biconditional introduction rule. Jessica is cooking if and only if it is late can be inferred via the biconditional introduction rule.