R/R₀ = f^{α−1}: at f=1 ⇒ 1; at α=1 ⇒ 1 (no-fractionation limits)

Sympy-exact witness of the Rayleigh fractionation law at the two no-fractionation limits. Setup: R/R₀ = f^{α−1}, where R is the instantaneous isotope ratio of the residual phase, R₀ the initial ratio, f the residual-phase mass fraction, α…