English
For any equivalence f: α ≃ α' we have (linearCombination_R v')(equivMapDomain f l) = linearCombination_R(v' ∘ f) l.
Русский
Для эквиваленции $f$ между индексами: линейная комбинация через $v'$ на $equivMapDomain f l$ равна линейной комбинации через $v'\circ f$ на $l$.
LaTeX
$$$(\operatorname{linearCombination}_R v')(\operatorname{equivMapDomain} f\, l) = \operatorname{linearCombination}_R(v'\circ f)\, l$$$
Lean4
@[simp]
theorem linearCombination_equivMapDomain (f : α ≃ α') (l : α →₀ R) :
(linearCombination R v') (equivMapDomain f l) = (linearCombination R (v' ∘ f)) l := by
rw [equivMapDomain_eq_mapDomain, linearCombination_mapDomain]