Fourth-element norm bound for case 39

Proved

D1Bound5.oneSmallFourth_39_growth

by tp · Oct 24, 2026 · Mathlib 0df444a (Lean v4.33.1)

diophantine-tuplesnumber-theory

For the specified anchors a, b and s, every element z below the stated norm cutoff for which az + 1, bz + 1 and sz + 1 are squares satisfies N(z) ≤ 4N(b)N(s).

Preamble

import Mathlib.Algebra.QuadraticAlgebra.Basic
import Mathlib.Algebra.Ring.Basic
import Mathlib.Algebra.Ring.Equiv
import Mathlib.Data.Finset.Card
import Mathlib.Data.Finset.Prod
import Mathlib.Data.Int.Interval
import Mathlib.Data.Int.Sqrt
import Mathlib.Data.List.Range
import Mathlib.Tactic.IntervalCases
import Mathlib.Tactic.Linarith
import Mathlib.Tactic.LinearCombination
import Definitions.Def_D1Bound5_Coordinates_Definitions
import Definitions.Def_D1Bound5_OneSmallFourthData5_Definitions
import Definitions.Def_D1Bound5_OneSmallThirdData_Definitions_002

Formal statement

section
namespace D1Bound5
open QuadInt
set_option maxRecDepth 32768
set_option maxHeartbeats 12000000























































theorem _root_.D1Bound5.oneSmallFourth_39_growth (z : QuadInt 0 6)
    (hz : z.norm < oneSmallTripleCutoff_39)
    (ha : ∃ q, q*q = oneSmallPairA_28*z+1)
    (hb : ∃ q, q*q = oneSmallPairB_28*z+1)
    (hs : ∃ q, q*q = oneSmallTripleS_39*z+1) :
    z.norm ≤ 4*oneSmallPairB_28.norm*oneSmallTripleS_39.norm := by sorry

end D1Bound5
end

Source

D1Bound5/OneSmallFourthData5.lean, lines 156-166, SHA-256 5c4d3dbb0b4b211a60602b6817a3d1f01003ce7efb46fbb3cb9a1abbd8a8cf83. Project: https://github.com/tomislav-math/d1-bound5-lean

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