English
If i is an index in 0,...,m-1, the map along the i-th edge yields the i-th edge of the path.
Русский
Если i принадлежит диапазону, отображение вдоль i-й ребра возвращает i-ю дугу пути.
LaTeX
$$$X.map(\mathrm{tr}\; (\mathrm{mkOfSucc}(i))^{op}(\mathrm{spineToSimplex}(m,h,f))) = f.arrow(i)$$$
Lean4
theorem spineToSimplex_edge (f : Path X m) (j l : ℕ) (hjl : j + l ≤ m) :
X.map (tr (intervalEdge j l hjl)).op (sx.spineToSimplex m h f) =
sx.spineToDiagonal l (by cutsat) (f.interval j l hjl) :=
by
dsimp only [spineToDiagonal, Function.comp_apply]
rw [← spineToSimplex_interval, ← FunctorToTypes.map_comp_apply, ← op_comp, ← tr_comp, diag_subinterval_eq]