Signed entry cross Block scaled error

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
import Definitions.Def_D1Bound5_RootMatrixSigns_Definitions

section
open scoped BigOperators NumberField
open Module

namespace D1Bound5








theorem _root_.D1Bound5.signed_entry_crossBlock_scaled_error
    {R : Type*} [CommRing R] (f : R →+* ℂ)
    (a b r : R) (u v : ℂ)
    (hu : u^2 = f a) (hv : v^2 = f b) (hr : r^2 = a*b+1)
    (hgood : SignedEntryGood f a b u v r) :
    ‖(f a*f b)*(u*f r*v)-(f a*f b)^2-(1/2 : ℂ)*(f a*f b)‖ <
      (2/15 : ℝ) := by sorry



end D1Bound5
end