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 not cold, then Robert is happy. It is cold if and only if Charles is working. James is curious. Charles is not working.
James is curious and Charles is not working can be inferred via the conjunction rule. Charles is not working and James is curious can be inferred via the conjunction rule. If it is cold, then Charles is working can be inferred via the biconditional elimination rule. If Charles works, then it is cold can be inferred via the biconditional elimination rule. It is not cold can be inferred via the biconditional elimination rule.