doc: Improve docs for basisLinear even

This commit is contained in:
jstoobysmith 2024-11-28 11:26:30 +00:00
parent 970b3a7436
commit 2fca6ac233

View file

@ -30,24 +30,30 @@ lemma n_cond₂ (n : ) : 1 + ((n + n) + 1) = 2 * n.succ := by
section theδs
/-- A helper function for what follows. -/
/-- The inclusion of `Fin n.succ` into `Fin (n.succ + n.succ)` via the first `n.succ`,
casted into `Fin (2 * n.succ)`. -/
def δ₁ (j : Fin n.succ) : Fin (2 * n.succ) := Fin.cast (split_equal n.succ) (Fin.castAdd n.succ j)
/-- A helper function for what follows. -/
/-- The inclusion of `Fin n.succ` into `Fin (n.succ + n.succ)` via the second `n.succ`,
casted into `Fin (2 * n.succ)`. -/
def δ₂ (j : Fin n.succ) : Fin (2 * n.succ) := Fin.cast (split_equal n.succ) (Fin.natAdd n.succ j)
/-- A helper function for what follows. -/
/-- The inclusion of `Fin n` into `Fin (1 + (n + n + 1))` via the first `n`,
casted into `Fin (2 * n.succ)`. -/
def δ!₁ (j : Fin n) : Fin (2 * n.succ) := Fin.cast (n_cond₂ n)
(Fin.natAdd 1 (Fin.castAdd 1 (Fin.castAdd n j)))
/-- A helper function for what follows. -/
/-- The inclusion of `Fin n` into `Fin (1 + (n + n + 1))` via the second `n`,
casted into `Fin (2 * n.succ)`. -/
def δ!₂ (j : Fin n) : Fin (2 * n.succ) := Fin.cast (n_cond₂ n)
(Fin.natAdd 1 (Fin.castAdd 1 (Fin.natAdd n j)))
/-- A helper function for what follows. -/
/-- The element of `Fin (1 + (n + n + 1))` corresponding to the first `1`,
casted into `Fin (2 * n.succ)`. -/
def δ!₃ : Fin (2 * n.succ) := (Fin.cast (n_cond₂ n) (Fin.castAdd ((n + n) + 1) 0))
/-- A helper function for what follows. -/
/-- The element of `Fin (1 + (n + n + 1))` corresponding to the second `1`,
casted into `Fin (2 * n.succ)`. -/
def δ!₄ : Fin (2 * n.succ) := (Fin.cast (n_cond₂ n) (Fin.natAdd 1 (Fin.natAdd (n + n) 0)))
lemma ext_δ (S T : Fin (2 * n.succ) → ) (h1 : ∀ i, S (δ₁ i) = T (δ₁ i))