Cross Block scaled det norm sq
ProvedD1Bound5.crossBlock_scaled_det_norm_sqdiophantine-tuplesnumber-theory
Squared modulus of the cross-block determinant after the two scaling steps. Stating the identity with squares avoids real square-root choices.
Preamble
import Mathlib.Algebra.QuadraticAlgebra.Basic import Mathlib.Algebra.Ring.Basic import Mathlib.Algebra.Ring.Equiv import Mathlib.Analysis.Complex.Basic import Mathlib.Analysis.Complex.Norm import Mathlib.Analysis.Complex.Polynomial.Basic import Mathlib.Data.Complex.Basic import Mathlib.Data.Finset.Card import Mathlib.Data.Int.GCD import Mathlib.LinearAlgebra.Dimension.Free import Mathlib.LinearAlgebra.Matrix.Determinant.Basic import Mathlib.LinearAlgebra.Matrix.ToLinearEquiv import Mathlib.NumberTheory.NumberField.InfinitePlace.TotallyRealComplex import Mathlib.NumberTheory.NumberField.Norm import Mathlib.Tactic.FieldSimp import Mathlib.Tactic.FinCases import Mathlib.Tactic.GCongr import Mathlib.Tactic.Linarith import Mathlib.Tactic.LinearCombination import Mathlib.Tactic.NormNum import Mathlib.Tactic.Ring
Formal statement
section
open scoped BigOperators NumberField
open Module
namespace D1Bound5
theorem _root_.D1Bound5.crossBlock_scaled_det_norm_sq
{R : Type*} [CommRing R] (f : R →+* ℂ)
(a b : Fin 3 → R) (u v : Fin 3 → ℂ)
(S : Fin 3 → Fin 3 → R)
(hu : ∀ i, (u i)^2 = f (a i)) (hv : ∀ j, (v j)^2 = f (b j)) :
‖Matrix.det (Matrix.of (fun i j => (f (a i)*u i)*f (S i j)*(f (b j)*v j)))‖^2 =
((‖f (a 0)‖*‖f (b 0)‖)*(‖f (a 1)‖*‖f (b 1)‖)*
(‖f (a 2)‖*‖f (b 2)‖))^3*‖f (Matrix.det (Matrix.of S))‖^2 := by sorry
end D1Bound5
end
Source
D1Bound5/CrossBlockTuple.lean, lines 41-84, SHA-256 4f7736bd25878caf4f646f90a08781588133d8497db784873e94a7e8e819b915. Project: https://github.com/tomislav-math/d1-bound5-lean