 Piketty bases his argument on a formula that relates the rate of return on capital ("r") to economic growth ("g"), where "r" includes profits, dividends, interest, rents and other income from capital and "g" is measured as growth of society's income or output.He argues that when the rate of growth is low, then wealth tends to accumulate more quickly from "r" than from labor and tends to accumulate more among the top 10% and 1%, increasing inequality.Thus the fundamental force for divergence and greater wealth inequality can be summed up in the inequality "r > g".