Consider the following premises. For all x_9, x_9 is a bartender if and only if x_9 is an office clerk. If Richard were an office clerk, then Richard is a bartender. Can we infer the following from them? If we can, name the inference rule being used: The fact that Richard were a bartender does not imply that Richard is an office clerk.
 From the fact that for all x_9, x_9 is a bartender if and only if x_9 is an office clerk we can infer that Richard is a bartender if and only if Richard is an office clerk via universal instantiation. Finally, from the fact that Richard is a bartender if and only if Richard is an office clerk we can infer that if Richard were a bartender, then Richard is an office clerk via biconditional elimination, which contradicts that The fact that Richard were a bartender does not imply that Richard is an office clerk. Therefore, the answer is no.