Research proof index

The metric tensor is non-degenerate. -/ lemma nondegenerate : (∀ (x : ContrMod d), ⟪x, y⟫ₘ = 0) ↔ y = 0 := by refine Iff.intro (fun h => ?) (fun h => ?) · exact (self_parity_eq_zero_iff _).mp ((symm _ _).trans $ h _) · simp [h] set_option backward.isDefEq.respectTransparency false in lemma matrix_apply_eq_iff_sub : ⟪x, Λ *ᵥ y⟫ₘ = ⟪x, Λ' *ᵥ y⟫ₘ ↔ ⟪x, (Λ...

Expanding contrContrToMatrix in terms of the standard basis.

Expanding contrContrToMatrixRe in terms of the standard basis.

Expansion of contrCoToMatrix in terms of the standard basis.

Expansion of (coBasis d) (coBasis d) in terms of the standard basis.

Expansion of contrCoUnitVal into basis.