Consider the following premises. John is an electrician if and only if Elisabeth is a nurse. For all x_14, x_14 will read a book if and only if x_14 is a nurse. Elisabeth is not reading a book. For all x_12, x_12 will work if and only if x_12 is an electrician. Can we infer the following from them? If we can, name the inference rule being used: John is working.
 From the fact that for all x_14, x_14 will read a book if and only if x_14 is a nurse we can infer that Elisabeth is reading a book if and only if Elisabeth is a nurse via universal instantiation. From the fact that for all x_12, x_12 will work if and only if x_12 is an electrician we can infer that John is working if and only if John is an electrician via universal instantiation. From the fact that Elisabeth is reading a book if and only if Elisabeth is a nurse, and that Elisabeth is not reading a book we can infer that Elisabeth is not a nurse via biconditional elimination. From the fact that John is an electrician if and only if Elisabeth is a nurse, and that Elisabeth is not a nurse we can infer that John is not an electrician via biconditional elimination. Finally, from the fact that John is working if and only if John is an electrician, and that John is not an electrician we can infer that John is not working via biconditional elimination, which contradicts that John is working. Therefore, the answer is no.