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: For all z, z is not a bartender. For all z, z will work if and only if z is a bartender. For all z, if z works, then z is reading a book. For all z, if z reads a book, then z is working.
For all z, z will work if and only if z will read a book can be inferred via the universal biconditional introduction rule. For all z, z will read a book if and only if z will work can be inferred via the universal biconditional introduction rule. For all z, if z works, then z is a bartender can be inferred via the universal biconditional elimination rule. For all z, if z were a bartender, then z is working can be inferred via the universal biconditional elimination rule. For all z, z will not work can be inferred via the universal biconditional elimination rule.