English
For any x in CliffordAlgebra Q, applying changeForm with zero_proof to x yields x themselves (self-application).
Русский
Для любого x ∈ CliffordAlgebra(Q) применение changeForm с нулевым доказательством к x даёт сам x.
LaTeX
$$$ changeForm(h)(x) = x \quad \text{for all } x \in CliffordAlgebra(Q)$$$
Lean4
theorem changeForm_self_apply (x : CliffordAlgebra Q) : changeForm (Q' := Q) changeForm.zero_proof x = x := by
induction x using CliffordAlgebra.left_induction with
| algebraMap => simp_rw [changeForm_algebraMap]
| add _ _ hx hy => rw [map_add, hx, hy]
| ι_mul _ _ hx => rw [changeForm_ι_mul, hx, LinearMap.zero_apply, map_zero, LinearMap.zero_apply, sub_zero]