The Lean 4 theorem `add` in the `ChapterHermiteBandCalculus` chapter of the timepiece formalization

import Definitions.Def_ChapterFullQuadraticEsa
import Definitions.Def_ChapterHermiteProductBasis
import Definitions.Def_ChapterHermiteProductCore
import Definitions.Def_ChapterNavierStokesDifferentialL2
-- Generated from ChapterHermiteBandCalculus.lean — theorem BookProof.HermiteBand.IsBand2.add
import Mathlib
import Definitions.Def_ChapterHermiteBandCalculus
import Definitions.Def_ChapterHermiteBandCalculus
open BookProof.HermiteBand







noncomputable section

open MvPolynomial BookProof.HermiteProductCore BookProof.HermiteProductBasis

variable {d : ℕ}

























open BookProof.NavierStokesFlow.DifferentialL2 BookProof.FullQuadratic

theorem BookProof.HermiteBand.IsBand2.add {T S : MvPolynomial (Fin d) ℂ →ₗ[ℂ] MvPolynomial (Fin d) ℂ}
    (hT : IsBand2 T) (hS : IsBand2 S) : IsBand2 (T + S) := by sorry