English
The Sigma.mk constructor intertwines with the Embedding map to relate embedded coordinates.
Русский
Конструктор Sigma.mk согласуется с отображением вложений Embedding.
LaTeX
$$$\\mathrm{Sigma.mk}_f(i,x)\\;\\mapsto\\; \\mathrm{Embedding}.map( f_{i,k} )$$$
Lean4
theorem funMap_unify_equiv {n : ℕ} (F : L.Functions n) (x : Fin n → Σˣ f) (i j : ι)
(hi : i ∈ upperBounds (range (Sigma.fst ∘ x))) (hj : j ∈ upperBounds (range (Sigma.fst ∘ x))) :
Structure.Sigma.mk f i (funMap F (unify f x i hi)) ≈ .mk f j (funMap F (unify f x j hj)) :=
by
obtain ⟨k, ik, jk⟩ := directed_of (· ≤ ·) i j
refine ⟨k, ik, jk, ?_⟩
rw [(f i k ik).map_fun, (f j k jk).map_fun, comp_unify, comp_unify]