Consider the following premises. For all x_9, if x_9 were a lawyer, then x_9 is climbing a mountain. For all x_9, if x_9 climbs a mountain, then x_9 is a mechanic. For all x_9, if x_9 were a cashier, then x_9 is a mechanic. For all x_9, if x_9 were an electrician, then x_9 is a cashier. For all x_9, x_9 is a lawyer or x_9 is an electrician. Can we infer the following from them? There is at least one x_9 for which neither x_9 is a mechanic nor x_9 is a taxi driver.
 From the fact that for all x_9, if x_9 were an electrician, then x_9 is a cashier, and that for all x_9, if x_9 were a cashier, then x_9 is a mechanic we can infer that for all x_9, if x_9 were an electrician, then x_9 is a mechanic. From the fact that for all x_9, if x_9 were a lawyer, then x_9 is climbing a mountain, and that for all x_9, if x_9 climbs a mountain, then x_9 is a mechanic we can infer that for all x_9, if x_9 were a lawyer, then x_9 is a mechanic. From the fact that for all x_9, if x_9 were a lawyer, then x_9 is a mechanic, that for all x_9, if x_9 were an electrician, then x_9 is a mechanic, and that for all x_9, x_9 is a lawyer or x_9 is an electrician we can infer that for all x_9, x_9 is a mechanic. Finally, from the fact that for all x_9, x_9 is a mechanic we can infer that for all x_9, x_9 is a mechanic or x_9 is a taxi driver, which contradicts that There is at least one x_9 for which neither x_9 is a mechanic nor x_9 is a taxi driver. Therefore, the answer is no.