Theorem: gamma_1/r_1 - gamma_2/r_2 = 0 at r_i = gamma_i (Wulff equilibrium ratio)

Theorem (Wulff-ratio canonical): the Wulff theorem states gamma_i/r_i = const for all facets at equilibrium. Setting r_i = gamma_i (proportional case, const = 1) gives gamma_1/r_1 = gamma_2/r_2 = 1, hence gamma_1/r_1 - gamma_2/r_2 = 0…