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: Barbara is not cooking. It is snowing or Robert is playing a game. It is not snowing. Barbara is cooking if and only if James is reading a book.
Robert is playing a game can be inferred via the disjunctive syllogism rule. Barbara is not cooking and it is not snowing can be inferred via the conjunction rule. It is not snowing and Barbara is not cooking can be inferred via the conjunction rule. If Barbara cooks, then James is reading a book can be inferred via the biconditional elimination rule. If James reads a book, then Barbara is cooking can be inferred via the biconditional elimination rule. James is not reading a book can be inferred via the biconditional elimination rule.