Dear Dr. Boli: Yesterday on Murray Avenue I parked behind a Japanese car that identified itself as a “PZEV,” which was spelled out in smaller letters as “Partial Zero Emissions Vehicle.” What does that mean? I haven’t been able to sleep since I saw it. —Sincerely, William C. Ford, Jr.

Dear Sir: You are right to be concerned, and your sleeplessness is indicative of a proper regard for the laws of mathematics. In their quest to squeeze ever more power out of a drop of oil, and to find a way to burn odoriferous chemicals without causing odoriferous smoke, automobile manufacturers have resorted to many a shady trick; but dividing zero into parts crosses the line from fraudulent to outright dangerous. There is no knowing what such a frontal assault on the foundations of arithmetic will lead to. If the rumors that General Motors has been selling unmarked Zero-Dividend Vehicles in the United States prove true, Dr. Boli trembles for the order of the universe.