The Lean 4 theorem `norm_sq_two` in the `ChapterHermiteQuadraticEsa` chapter of the timepiece formalization

-- Generated from ChapterHermiteQuadraticEsa.lean — theorem BookProof.HermiteQuadraticEsa.norm_sq_two
import Mathlib
import Definitions.Def_ChapterHermiteQuadraticEsa
open BookProof.HermiteQuadraticEsa














open MeasureTheory Complex MvPolynomial
open BookProof.HermiteProductCore BookProof.QgHermiteCore BookProof.QgHermiteFriedrichs
open BookProof.QgHermiteOscillator BookProof.FarisLavine BookProof.Starobinsky
open BookProof.StoneBridge BookProof.EsaClosure BookProof.ChapterStoneResolvent

noncomputable section

variable {d : ℕ}

theorem BookProof.HermiteQuadraticEsa.norm_sq_two (x : Vd 2) : ‖x‖ ^ 2 = (x 0) ^ 2 + (x 1) ^ 2 := by sorry