Fix a with scale Q>0Q>0. For exponents bib_i, normalized coordinates are yi=xi/Qbiy_i=x_i/Q^{b_i}; for a time distance τ\tau, one may also set s=τ/Qs=\tau/Q. The number QQ is constant within the chart.

Derivatives

For F(x)=AF~(y)F(x)=A\widetilde F(y), where AA is constant on this chart,

xIF=AQibiIiyIF~.\partial_x^I F=AQ^{-\sum_i b_i I_i}\partial_y^I\widetilde F.

Even if a variable scale q(x)q(x) is comparable to QQ on the band, differentiating a normalized chart holds QQ fixed. Replacing QQ by q(x)q(x) defines a different coordinate change and introduces chain-rule terms. Auxiliary parameters are held fixed unless their derivatives are explicitly included.