Seven years ago, the combined wealth of 388 billionaires equaled that of the poorest half of humanity, according to Oxfam International. This past January the equation was even more unbalanced: it took only eight billionaires, marking an unmistakable march toward increased concentration of wealth. Today that number has been reduced to five billionaires. Trying to understand such growing inequality is usually the purview of economists, but Bruce Boghosian, a professor of mathematics, thinks he has found another explanation—and a warning.