Inflation is the first derivative of prices (when that is positive, when it's negative it's deflation). So as long as inflation remains positive, prices will ne

Inflation is the first derivative of prices (when that is positive, when it's negative it's deflation). So as long as inflation remains positive, prices will never drop. Current economic theory maintains that the first derivative of prices must never become negative (no deflation), since that encourages saving money and slows the economy resulting in more deflation.