noncomputable def CoxeterGroup.generalizedReflection_local {B : Type u_1} [Fintype B] (M : CoxeterMatrix B) (β : B → ℝ) : (B → ℝ) → B → ℝ

Local copy of the generalized reflection along $\beta$: $s_\beta(v) = v - 2\,B_M(v, \beta)\,\beta$.