English
The map domain restriction respects composition: lmapDomain M R (g ∘ f) = (lmapDomain M R g) ∘ (lmapDomain M R f).
Русский
Ограничение области определения respects композицию: lmapDomain M R (g ∘ f) = (lmapDomain M R g) ∘ (lmapDomain M R f).
LaTeX
$$$\\text{lmapDomain}\\ M\\ R\\ (g\\circ f) = (\\text{lmapDomain}\\ M\\ R\\ g) \\circ (\\text{lmapDomain}\\ M\\ R\\ f)$$$
Lean4
/-- `Finsupp.mapDomain` as a `LinearEquiv`. -/
def linearEquiv (f : α ≃ α') : (α →₀ M) ≃ₗ[R] (α' →₀ M)
where
__ := lmapDomain M R f.toFun
invFun := mapDomain f.symm
left_inv _ := by simp [← mapDomain_comp]
right_inv _ := by simp [← mapDomain_comp]