To choose the pointelasticity or the arc elasticity?
选择点弹性还是弧弹性？
2
First, we seek the origin of the elasticity and the invention of the pointelasticity and the arc elasticity. We also search for their original paper respectively.
文中首先寻找弹性的由来始末，以及点弹性和弧弹性的产生过程，并各自找出它们的原始文献。
3
One way to evaluate this is by calculating the reduction in poverty for every percentage point increase in per capita income -- in economists' lingo, the income elasticity of poverty reduction.