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 Sarah cooks, then Robert is reading a book. Robert is reading a book if and only if it is cold. If Robert reads a book, then Sarah is cooking.
Sarah is cooking if and only if Robert is reading a book can be inferred via the biconditional introduction rule. Robert is reading a book if and only if Sarah is cooking can be inferred via the biconditional introduction rule. If Robert reads a book, then it is cold can be inferred via the biconditional elimination rule. If it is cold, then Robert is reading a book can be inferred via the biconditional elimination rule.