An evil dictator locks up all the academics in his country in a time of war. As the war worsens the army platoon left guarding the detention facility is called

An evil dictator locks up all the academics in his country in a time of war. As the war worsens the army platoon left guarding the detention facility is called away to the front, and leaves the academics unattended in their cells bottled water, canned food and no can openers. When the war is over and the dictatorship is collapsed, the detention facility is opened up. It's found that most of the humanities and social scientists have survived, having opened their cans by throwing them randomly at the walls until the cans broke open. The physicists had figured out the optimum angle at which to throw the can in order to reliably open it. Several mathematicians have suffered severe malnutrition, having successfully proven that "there exists a unique optimal throwing angle theta ..." The cell of a topologist was found empty, though a muffled screaming could be heard from one of his cans. A can opener is fetched, and the topologist is removed, covered in food, mumbling about an error in sign.