Table 1.

Mathematical summary of the three hypotheses.

	Relative size of changes	Effect
Hypothesis 1	$\left|\frac{\partial f}{\partial x}·dx\right|>\left|\frac{\partial f}{\partial y}·dy\right|$	wh > wr
Hypothesis 2	$\left|\frac{\partial f}{\partial x}·dx\right|<\left|\frac{\partial f}{\partial y}·dy\right|$	wh < wr
Hypothesis 3	$\left|\frac{\partial f}{\partial x}·dx\right|\cong \left|\frac{\partial f}{\partial y}·dy\right|$	wh ≅ wr