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 Joseph were a cashier, then Michael is a nurse. Patricia is reading a book if and only if Michael is a nurse. For all x_3, x_3 will not read a book.
If Patricia reads a book, then Michael is a nurse can be inferred via the biconditional elimination rule. If Michael were a nurse, then Patricia is reading a book can be inferred via the biconditional elimination rule.