Inflation (%ΔP) is equal to the rate of money growth (%Δ), plus the change in velocity (%Δ), minus the rate of output growth (%Δ). So if in the long run the growth rate of velocity and the growth rate of real GDP are exogenous constants (the former being dictated by changes in payment institutions and the latter dictated by the growth in the economy’s productive capacity), then the monetary growth rate and the inflation rate differ from each other by a fixed constant.