Conventional price elasticity of demand is a simplistic and elementary formula that has mathematical and economic deficiencies when applied to price (rates) and demand (balances) of deposit products: It does not recognize inverse relations between price and demand.
At its peak in 1300, the Mali Empire covered an area about twice the size of modern-day France and stretched to the west coast of Africa. In the late 19th century, during the Scramble for Africa, France seized control of Mali, making it a part of French Sudan.
Mali was famous in its day for its wealth, which was a result both of gold mines and international trade routes controlled by the empire. The Mali Empire grew to be one of the largest in Africa's history, and a pretty good namesake for the nation of Mali today.