Imports
/- Copyright (c) 2026 Gregory J. Loges. All rights reserved. Released under Apache 2.0 license as described in the file LICENSE. Authors: Gregory J. Loges -/ module public import Physlib.Mathematics.KroneckerDelta.Basic public import Physlib.Relativity.Tensors.RealTensor.Vector.Tensorial public import Physlib.QuantumMechanics.Operators.AngularMomentum

Commutation relations

i. Overview

In this module we compute the commutators for common operators acting on Schwartz maps on Space d.

Commutator lemmas come in three flavors:

      a_commutation_b lemmas are of the form ⁅a, b⁆ = (⋯).

      a_comp_b_commute and a_comp_commute lemmas are of the form a ∘ b = b ∘ a.

      a_comp_b_eq lemmas are of the form a ∘ b = b ∘ a + (⋯).

ii. Key results

    position_commutation_momentum : The canonical commutation relations.

    angularMomentum_commutation_position : The position operator transforms as a vector under infinitessimal rotations.

    angularMomentum_commutation_radiusRegPow : Functions of ‖x‖² commute with the angular momenta.

    angularMomentum_commutation_momentum : The momentum operator transforms as a vector under infinitessimal rotations.

    angularMomentum_commutation_angularMomentum : Angular momenta generate an 𝔰𝔬(d) algebra.

    angularMomentumSqr_commutation_angularMomentum : 𝐋² is a quadratic Casimir of 𝔰𝔬(d).

iii. Table of contents

    A. General

    B. Commutators

      B.1. Position / position

      B.2. Momentum / momentum

      B.3. Position / momentum

      B.4. Angular momentum / position

      B.5. Angular momentum / momentum

      B.6. Angular momentum / angular momentum

iv. References

@[expose] public section

A. General

lemma leibniz_lie (A B C : 𝓢(Space d, ℂ) →L[ℂ] 𝓢(Space d, ℂ)) : ⁅A ∘L B, C⁆ = A ∘L ⁅B, C⁆ + ⁅A, C⁆ ∘L B := d:ℕA:𝓢(Space d, ℂ) →L[ℂ] 𝓢(Space d, ℂ)B:𝓢(Space d, ℂ) →L[ℂ] 𝓢(Space d, ℂ)C:𝓢(Space d, ℂ) →L[ℂ] 𝓢(Space d, ℂ)⊢ ⁅A ∘SL B, C⁆ = A ∘SL ⁅B, C⁆ + ⁅A, C⁆ ∘SL B d:ℕA:𝓢(Space d, ℂ) →L[ℂ] 𝓢(Space d, ℂ)B:𝓢(Space d, ℂ) →L[ℂ] 𝓢(Space d, ℂ)C:𝓢(Space d, ℂ) →L[ℂ] 𝓢(Space d, ℂ)⊢ A ∘SL B * C - C * A ∘SL B = A ∘SL (B * C - C * B) + (A * C - C * A) ∘SL B All goals completed! 🐙lemma lie_leibniz (A B C : 𝓢(Space d, ℂ) →L[ℂ] 𝓢(Space d, ℂ)) : ⁅A, B ∘L C⁆ = B ∘L ⁅A, C⁆ + ⁅A, B⁆ ∘L C := d:ℕA:𝓢(Space d, ℂ) →L[ℂ] 𝓢(Space d, ℂ)B:𝓢(Space d, ℂ) →L[ℂ] 𝓢(Space d, ℂ)C:𝓢(Space d, ℂ) →L[ℂ] 𝓢(Space d, ℂ)⊢ ⁅A, B ∘SL C⁆ = B ∘SL ⁅A, C⁆ + ⁅A, B⁆ ∘SL C d:ℕA:𝓢(Space d, ℂ) →L[ℂ] 𝓢(Space d, ℂ)B:𝓢(Space d, ℂ) →L[ℂ] 𝓢(Space d, ℂ)C:𝓢(Space d, ℂ) →L[ℂ] 𝓢(Space d, ℂ)⊢ A * B ∘SL C - B ∘SL C * A = B ∘SL (A * C - C * A) + (A * B - B * A) ∘SL C All goals completed! 🐙lemma comp_eq_comp_add_commute (A B : 𝓢(Space d, ℂ) →L[ℂ] 𝓢(Space d, ℂ)) : A ∘L B = B ∘L A + ⁅A, B⁆ := d:ℕA:𝓢(Space d, ℂ) →L[ℂ] 𝓢(Space d, ℂ)B:𝓢(Space d, ℂ) →L[ℂ] 𝓢(Space d, ℂ)⊢ A ∘SL B = B ∘SL A + ⁅A, B⁆ d:ℕA:𝓢(Space d, ℂ) →L[ℂ] 𝓢(Space d, ℂ)B:𝓢(Space d, ℂ) →L[ℂ] 𝓢(Space d, ℂ)⊢ A ∘SL B = B ∘SL A + (A * B - B * A) All goals completed! 🐙lemma comp_eq_comp_sub_commute (A B : 𝓢(Space d, ℂ) →L[ℂ] 𝓢(Space d, ℂ)) : A ∘L B = B ∘L A - ⁅B, A⁆ := d:ℕA:𝓢(Space d, ℂ) →L[ℂ] 𝓢(Space d, ℂ)B:𝓢(Space d, ℂ) →L[ℂ] 𝓢(Space d, ℂ)⊢ A ∘SL B = B ∘SL A - ⁅B, A⁆ d:ℕA:𝓢(Space d, ℂ) →L[ℂ] 𝓢(Space d, ℂ)B:𝓢(Space d, ℂ) →L[ℂ] 𝓢(Space d, ℂ)⊢ A ∘SL B = B ∘SL A - (B * A - A * B) All goals completed! 🐙

B. Commutators

B.1. Position / position

Position operators commute: [xᵢ, xⱼ] = 0.

@[simp] lemma position_commutation_position : ⁅𝐱 i, 𝐱 j⁆ = 0 := d:ℕi:Fin dj:Fin d⊢ ⁅𝐱 i, 𝐱 j⁆ = 0 d:ℕi:Fin dj:Fin dx✝¹:𝓢(Space d, ℂ)x✝:Space d⊢ (⁅𝐱 i, 𝐱 j⁆ x✝¹) x✝ = (0 x✝¹) x✝ All goals completed! 🐙
All goals completed! 🐙@[simp] lemma position_commutation_radiusRegPow : ⁅𝐱 i, 𝐫₀[d] ε s⁆ = 0 := d:ℕi:Fin dε:ℝˣs:ℝ⊢ ⁅𝐱 i, 𝐫₀ ε s⁆ = 0 d:ℕi:Fin dε:ℝˣs:ℝx✝¹:𝓢(Space d, ℂ)x✝:Space d⊢ (⁅𝐱 i, 𝐫₀ ε s⁆ x✝¹) x✝ = (0 x✝¹) x✝ All goals completed! 🐙All goals completed! 🐙@[simp] lemma radiusRegPow_commutation_radiusRegPow : ⁅𝐫₀[d] ε s, 𝐫₀[d] ε t⁆ = 0 := d:ℕε:ℝˣs:ℝt:ℝ⊢ ⁅𝐫₀ ε s, 𝐫₀ ε t⁆ = 0 All goals completed! 🐙

B.2. Momentum / momentum

Momentum operators commute: [pᵢ, pⱼ] = 0.

@[simp] lemma momentum_commutation_momentum : ⁅𝐩 i, 𝐩 j⁆ = 0 := d:ℕi:Fin dj:Fin d⊢ ⁅𝐩 i, 𝐩 j⁆ = 0 d:ℕi:Fin dj:Fin dψ:𝓢(Space d, ℂ)x:Space d⊢ (⁅𝐩 i, 𝐩 j⁆ ψ) x = (0 ψ) x d:ℕi:Fin dj:Fin dψ:𝓢(Space d, ℂ)x:Space dhdiff:∀ (k : Fin d), Differentiable ℝ (Space.deriv k ⇑ψ)⊢ (⁅𝐩 i, 𝐩 j⁆ ψ) x = (0 ψ) x d:ℕi:Fin dj:Fin dψ:𝓢(Space d, ℂ)x:Space dhdiff:∀ (k : Fin d), Differentiable ℝ (Space.deriv k ⇑ψ)⊢ ((𝐩 i) ((𝐩 j) ψ)) x - ((𝐩 j) ((𝐩 i) ψ)) x = 0 All goals completed! 🐙
All goals completed! 🐙attribute [local instance 100] LieRing.ofAssociativeRing@[simp] lemma momentumSqr_commutation_momentum : ⁅𝐩[d] ⬝ᵥ 𝐩, 𝐩 i⁆ = 0 := d:ℕi:Fin d⊢ ⁅𝐩 ⬝ᵥ 𝐩, 𝐩 i⁆ = 0 All goals completed! 🐙All goals completed! 🐙

B.3. Position / momentum

The canonical commutation relations: [xᵢ, pⱼ] = iℏ δᵢⱼ𝟙.

d:ℕi:Fin dj:Fin dψ:𝓢(Space d, ℂ)x:Space d⊢ I * ↑↑ℏ * (-↑(x.val i) * Space.deriv j (⇑ψ) x + (x.val i • Space.deriv j (⇑ψ) x + (if j = i then 1 else 0) • ψ x)) = (((I * ↑↑ℏ) • δ[i,j] • ContinuousLinearMap.id ℂ 𝓢(Space d, ℂ)) ψ) x d:ℕi:Fin dψ:𝓢(Space d, ℂ)x:Space d⊢ I * ↑↑ℏ * (-↑(x.val i) * Space.deriv i (⇑ψ) x + (x.val i • Space.deriv i (⇑ψ) x + (if i = i then 1 else 0) • ψ x)) = (((I * ↑↑ℏ) • δ[i,i] • ContinuousLinearMap.id ℂ 𝓢(Space d, ℂ)) ψ) xd:ℕi:Fin dj:Fin dψ:𝓢(Space d, ℂ)x:Space dhne:i ≠ j⊢ I * ↑↑ℏ * (-↑(x.val i) * Space.deriv j (⇑ψ) x + (x.val i • Space.deriv j (⇑ψ) x + (if j = i then 1 else 0) • ψ x)) = (((I * ↑↑ℏ) • δ[i,j] • ContinuousLinearMap.id ℂ 𝓢(Space d, ℂ)) ψ) x d:ℕi:Fin dψ:𝓢(Space d, ℂ)x:Space d⊢ I * ↑↑ℏ * (-↑(x.val i) * Space.deriv i (⇑ψ) x + (x.val i • Space.deriv i (⇑ψ) x + (if i = i then 1 else 0) • ψ x)) = (((I * ↑↑ℏ) • δ[i,i] • ContinuousLinearMap.id ℂ 𝓢(Space d, ℂ)) ψ) x All goals completed! 🐙 d:ℕi:Fin dj:Fin dψ:𝓢(Space d, ℂ)x:Space dhne:i ≠ j⊢ I * ↑↑ℏ * (-↑(x.val i) * Space.deriv j (⇑ψ) x + (x.val i • Space.deriv j (⇑ψ) x + (if j = i then 1 else 0) • ψ x)) = (((I * ↑↑ℏ) • δ[i,j] • ContinuousLinearMap.id ℂ 𝓢(Space d, ℂ)) ψ) x All goals completed! 🐙
All goals completed! 🐙lemma position_position_commutation_momentum : ⁅𝐱 i ∘L 𝐱 j, 𝐩 k⁆ = (I * ℏ) • (δ[i,k] • 𝐱 j + δ[j,k] • 𝐱 i) := d:ℕi:Fin dj:Fin dk:Fin d⊢ ⁅𝐱 i ∘SL 𝐱 j, 𝐩 k⁆ = (I * ↑↑ℏ) • (δ[i,k] • 𝐱 j + δ[j,k] • 𝐱 i) All goals completed! 🐙lemma position_commutation_momentum_momentum : ⁅𝐱 i, 𝐩 j ∘L 𝐩 k⁆ = (I * ℏ) • (δ[i,k] • 𝐩 j + δ[i,j] • 𝐩 k) := d:ℕi:Fin dj:Fin dk:Fin d⊢ ⁅𝐱 i, 𝐩 j ∘SL 𝐩 k⁆ = (I * ↑↑ℏ) • (δ[i,k] • 𝐩 j + δ[i,j] • 𝐩 k) All goals completed! 🐙lemma position_commutation_momentumSqr : ⁅𝐱 i, 𝐩 ⬝ᵥ 𝐩⁆ = (2 * I * ℏ) • 𝐩 i := d:ℕi:Fin d⊢ ⁅𝐱 i, 𝐩 ⬝ᵥ 𝐩⁆ = (2 * I * ↑↑ℏ) • 𝐩 i All goals completed! 🐙d:ℕi:Fin dε:ℝˣs:ℝψ:𝓢(Space d, ℂ)x:Space dhne:‖x‖ ^ 2 + ↑ε ^ 2 ≠ 0hdiff1:DifferentiableAt ℝ (fun x => (‖x‖ ^ 2 + ↑ε ^ 2) ^ (s / 2)) xhdiff2:DifferentiableAt ℝ (fun x => x ^ (s / 2)) (‖x‖ ^ 2 + ↑ε ^ 2)hdiff3:DifferentiableAt ℝ (fun x => ‖x‖ ^ 2 + ↑ε ^ 2) x⊢ (fderiv ℝ (fun x => x ^ (s / 2)) (‖x‖ ^ 2 + ↑ε ^ 2) ∘SL (2 • (innerSL ℝ) x)) (Space.basis i) = s * (‖x‖ ^ 2 + ↑ε ^ 2) ^ (s / 2 - 1) * x.val i All goals completed! 🐙All goals completed! 🐙lemma radiusRegPow_commutation_momentumSqr : ⁅𝐫₀[d] ε s, 𝐩[d] ⬝ᵥ 𝐩⁆ = (2 * s * I * ℏ) • 𝐫₀ ε (s-2) ∘L (𝐱 ⬝ᵥ 𝐩) + (s * (d + s - 2) * ℏ ^ 2) • 𝐫₀ ε (s-2) - (ε ^ 2 * s * (s - 2) * ℏ ^ 2) • 𝐫₀ ε (s-4) := d:ℕε:ℝˣs:ℝ⊢ ⁅𝐫₀ ε s, 𝐩 ⬝ᵥ 𝐩⁆ = (2 * ↑s * I * ↑↑ℏ) • 𝐫₀ ε (s - 2) ∘SL (𝐱 ⬝ᵥ 𝐩) + (s * (↑d + s - 2) * ↑ℏ ^ 2) • 𝐫₀ ε (s - 2) - (↑ε ^ 2 * s * (s - 2) * ↑ℏ ^ 2) • 𝐫₀ ε (s - 4) calc _ = (s * I * ℏ) • ∑ i, ((𝐩 i ∘L 𝐫₀ ε (s-2)) ∘L 𝐱 i + 𝐫₀ ε (s-2) ∘L 𝐱 i ∘L 𝐩 i) := d:ℕε:ℝˣs:ℝ⊢ ⁅𝐫₀ ε s, 𝐩 ⬝ᵥ 𝐩⁆ = (↑s * I * ↑↑ℏ) • ∑ i, ((𝐩 i ∘SL 𝐫₀ ε (s - 2)) ∘SL 𝐱 i + 𝐫₀ ε (s - 2) ∘SL 𝐱 i ∘SL 𝐩 i) All goals completed! 🐙 _ = (s * I * ℏ) • ∑ i, (𝐫₀ ε (s-2) ∘L 𝐩 i ∘L 𝐱 i + 𝐫₀ ε (s-2) ∘L 𝐱 i ∘L 𝐩 i - (↑(s - 2) * I * ℏ) • 𝐫₀ ε (s-4) ∘L 𝐱 i ∘L 𝐱 i) := d:ℕε:ℝˣs:ℝ⊢ (↑s * I * ↑↑ℏ) • ∑ i, ((𝐩 i ∘SL 𝐫₀ ε (s - 2)) ∘SL 𝐱 i + 𝐫₀ ε (s - 2) ∘SL 𝐱 i ∘SL 𝐩 i) = (↑s * I * ↑↑ℏ) • ∑ i, (𝐫₀ ε (s - 2) ∘SL 𝐩 i ∘SL 𝐱 i + 𝐫₀ ε (s - 2) ∘SL 𝐱 i ∘SL 𝐩 i - (↑(s - 2) * I * ↑↑ℏ) • 𝐫₀ ε (s - 4) ∘SL 𝐱 i ∘SL 𝐱 i) d:ℕε:ℝˣs:ℝ⊢ (↑s * I * ↑↑ℏ) • ∑ x, (𝐫₀ ε (s - 2) ∘SL 𝐩 x ∘SL 𝐱 x + 𝐫₀ ε (s - 2) ∘SL 𝐱 x ∘SL 𝐩 x - (↑(s - 2) * I * ↑↑ℏ) • 𝐫₀ ε (s - 2 - 2) ∘SL 𝐱 x ∘SL 𝐱 x) = (↑s * I * ↑↑ℏ) • ∑ i, (𝐫₀ ε (s - 2) ∘SL 𝐩 i ∘SL 𝐱 i + 𝐫₀ ε (s - 2) ∘SL 𝐱 i ∘SL 𝐩 i - (↑(s - 2) * I * ↑↑ℏ) • 𝐫₀ ε (s - 4) ∘SL 𝐱 i ∘SL 𝐱 i) All goals completed! 🐙 _ = (s * I * ℏ) • ∑ i, ((2 : ℂ) • 𝐫₀ ε (s-2) ∘L 𝐱 i ∘L 𝐩 i - (I * ℏ) • 𝐫₀ ε (s-2) - ((s - 2) * I * ℏ) • 𝐫₀ ε (s-4) ∘L 𝐱 i ∘L 𝐱 i) := d:ℕε:ℝˣs:ℝ⊢ (↑s * I * ↑↑ℏ) • ∑ i, (𝐫₀ ε (s - 2) ∘SL 𝐩 i ∘SL 𝐱 i + 𝐫₀ ε (s - 2) ∘SL 𝐱 i ∘SL 𝐩 i - (↑(s - 2) * I * ↑↑ℏ) • 𝐫₀ ε (s - 4) ∘SL 𝐱 i ∘SL 𝐱 i) = (↑s * I * ↑↑ℏ) • ∑ i, (2 • 𝐫₀ ε (s - 2) ∘SL 𝐱 i ∘SL 𝐩 i - (I * ↑↑ℏ) • 𝐫₀ ε (s - 2) - ((↑s - 2) * I * ↑↑ℏ) • 𝐫₀ ε (s - 4) ∘SL 𝐱 i ∘SL 𝐱 i) All goals completed! 🐙 _ = (s * I * ℏ) • ((2 : ℂ) • 𝐫₀ ε (s-2) ∘L (𝐱 ⬝ᵥ 𝐩) - (d * I * ℏ) • 𝐫₀ ε (s-2) - ((s - 2) * I * ℏ) • 𝐫₀ ε (s-4) ∘L ∑ i, 𝐱 i ∘L 𝐱 i) := d:ℕε:ℝˣs:ℝ⊢ (↑s * I * ↑↑ℏ) • ∑ i, (2 • 𝐫₀ ε (s - 2) ∘SL 𝐱 i ∘SL 𝐩 i - (I * ↑↑ℏ) • 𝐫₀ ε (s - 2) - ((↑s - 2) * I * ↑↑ℏ) • 𝐫₀ ε (s - 4) ∘SL 𝐱 i ∘SL 𝐱 i) = (↑s * I * ↑↑ℏ) • (2 • 𝐫₀ ε (s - 2) ∘SL (𝐱 ⬝ᵥ 𝐩) - (↑d * I * ↑↑ℏ) • 𝐫₀ ε (s - 2) - ((↑s - 2) * I * ↑↑ℏ) • 𝐫₀ ε (s - 4) ∘SL ∑ i, 𝐱 i ∘SL 𝐱 i) All goals completed! 🐙 _ = (2 * s * I * ℏ) • 𝐫₀ ε (s-2) ∘L (𝐱 ⬝ᵥ 𝐩) + (s * (d + s - 2) * ℏ ^ 2) • 𝐫₀ ε (s-2) - (ε ^ 2 * s * (s - 2) * ℏ ^ 2) • 𝐫₀ ε (s-4) := d:ℕε:ℝˣs:ℝ⊢ (↑s * I * ↑↑ℏ) • (2 • 𝐫₀ ε (s - 2) ∘SL (𝐱 ⬝ᵥ 𝐩) - (↑d * I * ↑↑ℏ) • 𝐫₀ ε (s - 2) - ((↑s - 2) * I * ↑↑ℏ) • 𝐫₀ ε (s - 4) ∘SL ∑ i, 𝐱 i ∘SL 𝐱 i) = (2 * ↑s * I * ↑↑ℏ) • 𝐫₀ ε (s - 2) ∘SL (𝐱 ⬝ᵥ 𝐩) + (s * (↑d + s - 2) * ↑ℏ ^ 2) • 𝐫₀ ε (s - 2) - (↑ε ^ 2 * s * (s - 2) * ↑ℏ ^ 2) • 𝐫₀ ε (s - 4) simp_rw d:ℕε:ℝˣs:ℝ⊢ (↑s * I * ↑↑ℏ) • (2 • 𝐫₀ ε (s - 2) ∘SL (𝐱 ⬝ᵥ 𝐩) - (↑d * I * ↑↑ℏ) • 𝐫₀ ε (s - 2) - ((↑s - 2) * I * ↑↑ℏ) • 𝐫₀ ε (s - 4) ∘SL ∑ i, 𝐱 i ∘SL 𝐱 i) = (2 * ↑s * I * ↑↑ℏ) • 𝐫₀ ε (s - 2) ∘SL (𝐱 ⬝ᵥ 𝐩) + (s * (↑d + s - 2) * ↑ℏ ^ 2) • 𝐫₀ ε (s - 2) - (↑ε ^ 2 * s * (s - 2) * ↑ℏ ^ 2) • 𝐫₀ ε (s - 4)d:ℕε:ℝˣs:ℝ⊢ (↑s * I * ↑↑ℏ) • (2 • 𝐫₀ ε (s - 2) ∘SL (𝐱 ⬝ᵥ 𝐩) - (↑d * I * ↑↑ℏ) • 𝐫₀ ε (s - 2) - ((↑s - 2) * I * ↑↑ℏ) • 𝐫₀ ε (s - 4) ∘SL (𝐫₀ ε 2 - ↑ε ^ 2 • ContinuousLinearMap.id ℂ 𝓢(Space d, ℂ))) = (2 * ↑s * I * ↑↑ℏ) • 𝐫₀ ε (s - 2) ∘SL (𝐱 ⬝ᵥ 𝐩) + (s * (↑d + s - 2) * ↑ℏ ^ 2) • 𝐫₀ ε (s - 2) - (↑ε ^ 2 * s * (s - 2) * ↑ℏ ^ 2) • 𝐫₀ ε (s - 4) d:ℕε:ℝˣs:ℝ⊢ (↑s * I * ↑↑ℏ) • (2 • 𝐫₀ ε (s - 2) ∘SL (𝐱 ⬝ᵥ 𝐩) - (↑d * I * ↑↑ℏ) • 𝐫₀ ε (s - 2) - ((↑s - 2) * I * ↑↑ℏ) • (𝐫₀ ε (s - 4) ∘SL 𝐫₀ ε 2 - 𝐫₀ ε (s - 4) ∘SL (↑ε ^ 2 • ContinuousLinearMap.id ℂ 𝓢(Space d, ℂ)))) = (2 * ↑s * I * ↑↑ℏ) • 𝐫₀ ε (s - 2) ∘SL (𝐱 ⬝ᵥ 𝐩) + (s * (↑d + s - 2) * ↑ℏ ^ 2) • 𝐫₀ ε (s - 2) - (↑ε ^ 2 * s * (s - 2) * ↑ℏ ^ 2) • 𝐫₀ ε (s - 4) d:ℕε:ℝˣs:ℝ⊢ (↑s * I * ↑↑ℏ) • (2 • 𝐫₀ ε (s - 2) ∘SL (𝐱 ⬝ᵥ 𝐩) - (↑d * I * ↑↑ℏ) • 𝐫₀ ε (s - 2) - ((↑s - 2) * I * ↑↑ℏ) • (𝐫₀ ε (s - 4) ∘SL 𝐫₀ ε 2 - ↑ε ^ 2 • 𝐫₀ ε (s - 4) ∘SL ContinuousLinearMap.id ℂ 𝓢(Space d, ℂ))) = (2 * ↑s * I * ↑↑ℏ) • 𝐫₀ ε (s - 2) ∘SL (𝐱 ⬝ᵥ 𝐩) + (s * (↑d + s - 2) * ↑ℏ ^ 2) • 𝐫₀ ε (s - 2) - (↑ε ^ 2 * s * (s - 2) * ↑ℏ ^ 2) • 𝐫₀ ε (s - 4) d:ℕε:ℝˣs:ℝ⊢ (↑s * I * ↑↑ℏ) • (2 • 𝐫₀ ε (s - 2) ∘SL (𝐱 ⬝ᵥ 𝐩) - (↑d * I * ↑↑ℏ) • 𝐫₀ ε (s - 2) - ((↑s - 2) * I * ↑↑ℏ) • (𝐫₀ ε (s - 4) ∘SL 𝐫₀ ε 2 - ↑ε ^ 2 • 𝐫₀ ε (s - 4))) = (2 * ↑s * I * ↑↑ℏ) • 𝐫₀ ε (s - 2) ∘SL (𝐱 ⬝ᵥ 𝐩) + (s * (↑d + s - 2) * ↑ℏ ^ 2) • 𝐫₀ ε (s - 2) - (↑ε ^ 2 * s * (s - 2) * ↑ℏ ^ 2) • 𝐫₀ ε (s - 4) d:ℕε:ℝˣs:ℝ⊢ (↑s * I * ↑↑ℏ) • (2 • 𝐫₀ ε (s - 2) ∘SL (𝐱 ⬝ᵥ 𝐩) - (↑d * I * ↑↑ℏ) • 𝐫₀ ε (s - 2) - ((↑s - 2) * I * ↑↑ℏ) • (𝐫₀ ε (s - 4 + 2) - ↑ε ^ 2 • 𝐫₀ ε (s - 4))) = (2 * ↑s * I * ↑↑ℏ) • 𝐫₀ ε (s - 2) ∘SL (𝐱 ⬝ᵥ 𝐩) + (s * (↑d + s - 2) * ↑ℏ ^ 2) • 𝐫₀ ε (s - 2) - (↑ε ^ 2 * s * (s - 2) * ↑ℏ ^ 2) • 𝐫₀ ε (s - 4)] d:ℕε:ℝˣs:ℝ⊢ (↑s * I * ↑↑ℏ * 2) • 𝐫₀ ε (s - 2) ∘SL (𝐱 ⬝ᵥ 𝐩) - (↑s * I * ↑↑ℏ * (↑d * I * ↑↑ℏ)) • 𝐫₀ ε (s - 2) - ((↑s * I * ↑↑ℏ * ((↑s - 2) * I * ↑↑ℏ)) • 𝐫₀ ε (s - 4 + 2) - (↑s * I * ↑↑ℏ * ((↑s - 2) * I * ↑↑ℏ * ↑↑ε ^ 2)) • 𝐫₀ ε (s - 4)) = (2 * ↑s * I * ↑↑ℏ) • 𝐫₀ ε (s - 2) ∘SL (𝐱 ⬝ᵥ 𝐩) + (↑s * (↑d + ↑s - 2) * ↑↑ℏ ^ 2) • 𝐫₀ ε (s - 2) - (↑↑ε ^ 2 * ↑s * (↑s - 2) * ↑↑ℏ ^ 2) • 𝐫₀ ε (s - 4) d:ℕε:ℝˣs:ℝ⊢ (↑s * I * ↑↑ℏ * 2) • 𝐫₀ ε (-2 + s) ∘SL (𝐱 ⬝ᵥ 𝐩) - (↑s * I ^ 2 * ↑↑ℏ ^ 2 * ↑d) • 𝐫₀ ε (-2 + s) - ((-(↑s * I ^ 2 * ↑↑ℏ ^ 2 * 2) + ↑s ^ 2 * I ^ 2 * ↑↑ℏ ^ 2) • 𝐫₀ ε (-2 + s) - (-(↑s * I ^ 2 * ↑↑ℏ ^ 2 * ↑↑ε ^ 2 * 2) + ↑s ^ 2 * I ^ 2 * ↑↑ℏ ^ 2 * ↑↑ε ^ 2) • 𝐫₀ ε (-4 + s)) = (↑s * I * ↑↑ℏ * 2) • 𝐫₀ ε (-2 + s) ∘SL (𝐱 ⬝ᵥ 𝐩) + (-(↑s * ↑↑ℏ ^ 2 * 2) + ↑s * ↑↑ℏ ^ 2 * ↑d + ↑s ^ 2 * ↑↑ℏ ^ 2) • 𝐫₀ ε (-2 + s) - (-(↑s * ↑↑ℏ ^ 2 * ↑↑ε ^ 2 * 2) + ↑s ^ 2 * ↑↑ℏ ^ 2 * ↑↑ε ^ 2) • 𝐫₀ ε (-4 + s) simp_rw d:ℕε:ℝˣs:ℝ⊢ (↑s * I * ↑↑ℏ * 2) • 𝐫₀ ε (-2 + s) ∘SL (𝐱 ⬝ᵥ 𝐩) - (↑s * I ^ 2 * ↑↑ℏ ^ 2 * ↑d) • 𝐫₀ ε (-2 + s) - ((-(↑s * I ^ 2 * ↑↑ℏ ^ 2 * 2) + ↑s ^ 2 * I ^ 2 * ↑↑ℏ ^ 2) • 𝐫₀ ε (-2 + s) - (-(↑s * I ^ 2 * ↑↑ℏ ^ 2 * ↑↑ε ^ 2 * 2) + ↑s ^ 2 * I ^ 2 * ↑↑ℏ ^ 2 * ↑↑ε ^ 2) • 𝐫₀ ε (-4 + s)) = (↑s * I * ↑↑ℏ * 2) • 𝐫₀ ε (-2 + s) ∘SL (𝐱 ⬝ᵥ 𝐩) + (-(↑s * ↑↑ℏ ^ 2 * 2) + ↑s * ↑↑ℏ ^ 2 * ↑d + ↑s ^ 2 * ↑↑ℏ ^ 2) • 𝐫₀ ε (-2 + s) - (-(↑s * ↑↑ℏ ^ 2 * ↑↑ε ^ 2 * 2) + ↑s ^ 2 * ↑↑ℏ ^ 2 * ↑↑ε ^ 2) • 𝐫₀ ε (-4 + s)d:ℕε:ℝˣs:ℝ⊢ (↑s * I * ↑↑ℏ * 2) • 𝐫₀ ε (-2 + s) ∘SL (𝐱 ⬝ᵥ 𝐩) - (↑s * I ^ 2 * ↑↑ℏ ^ 2 * ↑d) • 𝐫₀ ε (-2 + s) - (-(↑s * I ^ 2 * ↑↑ℏ ^ 2 * 2) + ↑s ^ 2 * I ^ 2 * ↑↑ℏ ^ 2) • 𝐫₀ ε (-2 + s) + (-(↑s * I ^ 2 * ↑↑ℏ ^ 2 * ↑↑ε ^ 2 * 2) + ↑s ^ 2 * I ^ 2 * ↑↑ℏ ^ 2 * ↑↑ε ^ 2) • 𝐫₀ ε (-4 + s) = (↑s * I * ↑↑ℏ * 2) • 𝐫₀ ε (-2 + s) ∘SL (𝐱 ⬝ᵥ 𝐩) + (-(↑s * ↑↑ℏ ^ 2 * 2) + ↑s * ↑↑ℏ ^ 2 * ↑d + ↑s ^ 2 * ↑↑ℏ ^ 2) • 𝐫₀ ε (-2 + s) - (-(↑s * ↑↑ℏ ^ 2 * ↑↑ε ^ 2 * 2) + ↑s ^ 2 * ↑↑ℏ ^ 2 * ↑↑ε ^ 2) • 𝐫₀ ε (-4 + s) d:ℕε:ℝˣs:ℝ⊢ (↑s * I * ↑↑ℏ * 2) • 𝐫₀ ε (-2 + s) ∘SL (𝐱 ⬝ᵥ 𝐩) - ((↑s * I ^ 2 * ↑↑ℏ ^ 2 * ↑d) • 𝐫₀ ε (-2 + s) + (-(↑s * I ^ 2 * ↑↑ℏ ^ 2 * 2) + ↑s ^ 2 * I ^ 2 * ↑↑ℏ ^ 2) • 𝐫₀ ε (-2 + s)) + (-(↑s * I ^ 2 * ↑↑ℏ ^ 2 * ↑↑ε ^ 2 * 2) + ↑s ^ 2 * I ^ 2 * ↑↑ℏ ^ 2 * ↑↑ε ^ 2) • 𝐫₀ ε (-4 + s) = (↑s * I * ↑↑ℏ * 2) • 𝐫₀ ε (-2 + s) ∘SL (𝐱 ⬝ᵥ 𝐩) + (-(↑s * ↑↑ℏ ^ 2 * 2) + ↑s * ↑↑ℏ ^ 2 * ↑d + ↑s ^ 2 * ↑↑ℏ ^ 2) • 𝐫₀ ε (-2 + s) - (-(↑s * ↑↑ℏ ^ 2 * ↑↑ε ^ 2 * 2) + ↑s ^ 2 * ↑↑ℏ ^ 2 * ↑↑ε ^ 2) • 𝐫₀ ε (-4 + s) d:ℕε:ℝˣs:ℝ⊢ (↑s * I * ↑↑ℏ * 2) • 𝐫₀ ε (-2 + s) ∘SL (𝐱 ⬝ᵥ 𝐩) - (↑s * I ^ 2 * ↑↑ℏ ^ 2 * ↑d + (-(↑s * I ^ 2 * ↑↑ℏ ^ 2 * 2) + ↑s ^ 2 * I ^ 2 * ↑↑ℏ ^ 2)) • 𝐫₀ ε (-2 + s) + (-(↑s * I ^ 2 * ↑↑ℏ ^ 2 * ↑↑ε ^ 2 * 2) + ↑s ^ 2 * I ^ 2 * ↑↑ℏ ^ 2 * ↑↑ε ^ 2) • 𝐫₀ ε (-4 + s) = (↑s * I * ↑↑ℏ * 2) • 𝐫₀ ε (-2 + s) ∘SL (𝐱 ⬝ᵥ 𝐩) + (-(↑s * ↑↑ℏ ^ 2 * 2) + ↑s * ↑↑ℏ ^ 2 * ↑d + ↑s ^ 2 * ↑↑ℏ ^ 2) • 𝐫₀ ε (-2 + s) - (-(↑s * ↑↑ℏ ^ 2 * ↑↑ε ^ 2 * 2) + ↑s ^ 2 * ↑↑ℏ ^ 2 * ↑↑ε ^ 2) • 𝐫₀ ε (-4 + s) d:ℕε:ℝˣs:ℝ⊢ (↑s * I * ↑↑ℏ * 2) • 𝐫₀ ε (-2 + s) ∘SL (𝐱 ⬝ᵥ 𝐩) - (↑s * -1 * ↑↑ℏ ^ 2 * ↑d + (-(↑s * -1 * ↑↑ℏ ^ 2 * 2) + ↑s ^ 2 * -1 * ↑↑ℏ ^ 2)) • 𝐫₀ ε (-2 + s) + (-(↑s * -1 * ↑↑ℏ ^ 2 * ↑↑ε ^ 2 * 2) + ↑s ^ 2 * -1 * ↑↑ℏ ^ 2 * ↑↑ε ^ 2) • 𝐫₀ ε (-4 + s) = (↑s * I * ↑↑ℏ * 2) • 𝐫₀ ε (-2 + s) ∘SL (𝐱 ⬝ᵥ 𝐩) + (-(↑s * ↑↑ℏ ^ 2 * 2) + ↑s * ↑↑ℏ ^ 2 * ↑d + ↑s ^ 2 * ↑↑ℏ ^ 2) • 𝐫₀ ε (-2 + s) - (-(↑s * ↑↑ℏ ^ 2 * ↑↑ε ^ 2 * 2) + ↑s ^ 2 * ↑↑ℏ ^ 2 * ↑↑ε ^ 2) • 𝐫₀ ε (-4 + s) d:ℕε:ℝˣs:ℝ⊢ (↑s * I * ↑↑ℏ * 2) • 𝐫₀ ε (-2 + s) ∘SL (𝐱 ⬝ᵥ 𝐩) + -((↑s * -1 * ↑↑ℏ ^ 2 * ↑d + (-(↑s * -1 * ↑↑ℏ ^ 2 * 2) + ↑s ^ 2 * -1 * ↑↑ℏ ^ 2)) • 𝐫₀ ε (-2 + s)) + (-(↑s * -1 * ↑↑ℏ ^ 2 * ↑↑ε ^ 2 * 2) + ↑s ^ 2 * -1 * ↑↑ℏ ^ 2 * ↑↑ε ^ 2) • 𝐫₀ ε (-4 + s) = (↑s * I * ↑↑ℏ * 2) • 𝐫₀ ε (-2 + s) ∘SL (𝐱 ⬝ᵥ 𝐩) + (-(↑s * ↑↑ℏ ^ 2 * 2) + ↑s * ↑↑ℏ ^ 2 * ↑d + ↑s ^ 2 * ↑↑ℏ ^ 2) • 𝐫₀ ε (-2 + s) + -((-(↑s * ↑↑ℏ ^ 2 * ↑↑ε ^ 2 * 2) + ↑s ^ 2 * ↑↑ℏ ^ 2 * ↑↑ε ^ 2) • 𝐫₀ ε (-4 + s)) d:ℕε:ℝˣs:ℝ⊢ (↑s * I * ↑↑ℏ * 2) • 𝐫₀ ε (-2 + s) ∘SL (𝐱 ⬝ᵥ 𝐩) + -(↑s * -1 * ↑↑ℏ ^ 2 * ↑d + (-(↑s * -1 * ↑↑ℏ ^ 2 * 2) + ↑s ^ 2 * -1 * ↑↑ℏ ^ 2)) • 𝐫₀ ε (-2 + s) + (-(↑s * -1 * ↑↑ℏ ^ 2 * ↑↑ε ^ 2 * 2) + ↑s ^ 2 * -1 * ↑↑ℏ ^ 2 * ↑↑ε ^ 2) • 𝐫₀ ε (-4 + s) = (↑s * I * ↑↑ℏ * 2) • 𝐫₀ ε (-2 + s) ∘SL (𝐱 ⬝ᵥ 𝐩) + (-(↑s * ↑↑ℏ ^ 2 * 2) + ↑s * ↑↑ℏ ^ 2 * ↑d + ↑s ^ 2 * ↑↑ℏ ^ 2) • 𝐫₀ ε (-2 + s) + -(-(↑s * ↑↑ℏ ^ 2 * ↑↑ε ^ 2 * 2) + ↑s ^ 2 * ↑↑ℏ ^ 2 * ↑↑ε ^ 2) • 𝐫₀ ε (-4 + s)] All goals completed! 🐙

B.4. Angular momentum / position

lemma angularMomentum_commutation_position : ⁅𝐋 i j, 𝐱 k⁆ = (I * ℏ) • (δ[i,k] • 𝐱 j - δ[j,k] • 𝐱 i) := d:ℕi:Fin dj:Fin dk:Fin d⊢ ⁅𝐋 i j, 𝐱 k⁆ = (I * ↑↑ℏ) • (δ[i,k] • 𝐱 j - δ[j,k] • 𝐱 i) d:ℕi:Fin dj:Fin dk:Fin d⊢ ⁅𝐋 i j, 𝐱 k⁆ = 𝐱 i ∘SL ⁅𝐩 j, 𝐱 k⁆ - 𝐱 j ∘SL ⁅𝐩 i, 𝐱 k⁆d:ℕi:Fin dj:Fin dk:Fin d⊢ 𝐱 i ∘SL ⁅𝐩 j, 𝐱 k⁆ - 𝐱 j ∘SL ⁅𝐩 i, 𝐱 k⁆ = (I * ↑↑ℏ) • (δ[i,k] • 𝐱 j - δ[j,k] • 𝐱 i) d:ℕi:Fin dj:Fin dk:Fin d⊢ ⁅𝐋 i j, 𝐱 k⁆ = 𝐱 i ∘SL ⁅𝐩 j, 𝐱 k⁆ - 𝐱 j ∘SL ⁅𝐩 i, 𝐱 k⁆ All goals completed! 🐙 All goals completed! 🐙@[simp] lemma angularMomentum_commutation_radiusRegPow : ⁅𝐋 i j, 𝐫₀[d] ε s⁆ = 0 := d:ℕi:Fin dj:Fin dε:ℝˣs:ℝ⊢ ⁅𝐋 i j, 𝐫₀ ε s⁆ = 0 d:ℕi:Fin dj:Fin dε:ℝˣs:ℝ⊢ ⁅𝐋 i j, 𝐫₀ ε s⁆ = 𝐱 i ∘SL ⁅𝐩 j, 𝐫₀ ε s⁆ - 𝐱 j ∘SL ⁅𝐩 i, 𝐫₀ ε s⁆d:ℕi:Fin dj:Fin dε:ℝˣs:ℝ⊢ 𝐱 i ∘SL ⁅𝐩 j, 𝐫₀ ε s⁆ - 𝐱 j ∘SL ⁅𝐩 i, 𝐫₀ ε s⁆ = 0 d:ℕi:Fin dj:Fin dε:ℝˣs:ℝ⊢ ⁅𝐋 i j, 𝐫₀ ε s⁆ = 𝐱 i ∘SL ⁅𝐩 j, 𝐫₀ ε s⁆ - 𝐱 j ∘SL ⁅𝐩 i, 𝐫₀ ε s⁆ All goals completed! 🐙 All goals completed! 🐙All goals completed! 🐙@[simp] lemma angularMomentumSqr_commutation_radiusRegPow : ⁅𝐋²[d], 𝐫₀[d] ε s⁆ = 0 := d:ℕε:ℝˣs:ℝ⊢ ⁅𝐋², 𝐫₀ ε s⁆ = 0 All goals completed! 🐙All goals completed! 🐙

B.5. Angular momentum / momentum

lemma angularMomentum_commutation_momentum : ⁅𝐋 i j, 𝐩 k⁆ = (I * ℏ) • (δ[i,k] • 𝐩 j - δ[j,k] • 𝐩 i) := d:ℕi:Fin dj:Fin dk:Fin d⊢ ⁅𝐋 i j, 𝐩 k⁆ = (I * ↑↑ℏ) • (δ[i,k] • 𝐩 j - δ[j,k] • 𝐩 i) d:ℕi:Fin dj:Fin dk:Fin d⊢ ⁅𝐋 i j, 𝐩 k⁆ = ⁅𝐱 i, 𝐩 k⁆ ∘SL 𝐩 j - ⁅𝐱 j, 𝐩 k⁆ ∘SL 𝐩 id:ℕi:Fin dj:Fin dk:Fin d⊢ ⁅𝐱 i, 𝐩 k⁆ ∘SL 𝐩 j - ⁅𝐱 j, 𝐩 k⁆ ∘SL 𝐩 i = (I * ↑↑ℏ) • (δ[i,k] • 𝐩 j - δ[j,k] • 𝐩 i) d:ℕi:Fin dj:Fin dk:Fin d⊢ ⁅𝐋 i j, 𝐩 k⁆ = ⁅𝐱 i, 𝐩 k⁆ ∘SL 𝐩 j - ⁅𝐱 j, 𝐩 k⁆ ∘SL 𝐩 i All goals completed! 🐙 All goals completed! 🐙All goals completed! 🐙@[simp] lemma angularMomentum_commutation_momentumSqr : ⁅𝐋 i j, 𝐩[d] ⬝ᵥ 𝐩⁆ = 0 := d:ℕi:Fin dj:Fin d⊢ ⁅𝐋 i j, 𝐩 ⬝ᵥ 𝐩⁆ = 0 All goals completed! 🐙All goals completed! 🐙@[simp] lemma angularMomentumSqr_commutation_momentumSqr : ⁅𝐋²[d], 𝐩[d] ⬝ᵥ 𝐩⁆ = 0 := d:ℕ⊢ ⁅𝐋², 𝐩 ⬝ᵥ 𝐩⁆ = 0 All goals completed! 🐙

B.6. Angular momentum / angular momentum

lemma angularMomentum_commutation_angularMomentum : ⁅𝐋 i j, 𝐋 k l⁆ = (I * ℏ) • (δ[i,k] • 𝐋 j l - δ[i,l] • 𝐋 j k - δ[j,k] • 𝐋 i l + δ[j,l] • 𝐋 i k) := d:ℕi:Fin dj:Fin dk:Fin dl:Fin d⊢ ⁅𝐋 i j, 𝐋 k l⁆ = (I * ↑↑ℏ) • (δ[i,k] • 𝐋 j l - δ[i,l] • 𝐋 j k - δ[j,k] • 𝐋 i l + δ[j,l] • 𝐋 i k) nth_rw 2 [d:ℕi:Fin dj:Fin dk:Fin dl:Fin d⊢ ⁅𝐋 i j, 𝐱 k ∘SL 𝐩 l - 𝐱 l ∘SL 𝐩 k⁆ = (I * ↑↑ℏ) • (δ[i,k] • 𝐋 j l - δ[i,l] • 𝐋 j k - δ[j,k] • 𝐋 i l + δ[j,l] • 𝐋 i k)d:ℕi:Fin dj:Fin dk:Fin dl:Fin d⊢ ⁅𝐋 i j, 𝐱 k ∘SL 𝐩 l - 𝐱 l ∘SL 𝐩 k⁆ = (I * ↑↑ℏ) • (δ[i,k] • 𝐋 j l - δ[i,l] • 𝐋 j k - δ[j,k] • 𝐋 i l + δ[j,l] • 𝐋 i k) d:ℕi:Fin dj:Fin dk:Fin dl:Fin d⊢ (I * ↑↑ℏ) • (δ[i,l] • 𝐱 k ∘SL 𝐩 j - δ[j,l] • 𝐱 k ∘SL 𝐩 i + (δ[i,k] • 𝐱 j ∘SL 𝐩 l - δ[j,k] • 𝐱 i ∘SL 𝐩 l) - (δ[i,k] • 𝐱 l ∘SL 𝐩 j - δ[j,k] • 𝐱 l ∘SL 𝐩 i + (δ[i,l] • 𝐱 j ∘SL 𝐩 k - δ[j,l] • 𝐱 i ∘SL 𝐩 k))) = (I * ↑↑ℏ) • (δ[i,k] • 𝐋 j l - δ[i,l] • 𝐋 j k - δ[j,k] • 𝐋 i l + δ[j,l] • 𝐋 i k) d:ℕi:Fin dj:Fin dk:Fin dl:Fin d⊢ (I * ↑↑ℏ) • (δ[i,l] • 𝐱 k ∘SL 𝐩 j - δ[j,l] • 𝐱 k ∘SL 𝐩 i + (δ[i,k] • 𝐱 j ∘SL 𝐩 l - δ[j,k] • 𝐱 i ∘SL 𝐩 l) - (δ[i,k] • 𝐱 l ∘SL 𝐩 j - δ[j,k] • 𝐱 l ∘SL 𝐩 i + (δ[i,l] • 𝐱 j ∘SL 𝐩 k - δ[j,l] • 𝐱 i ∘SL 𝐩 k))) = (I * ↑↑ℏ) • (δ[i,k] • (𝐱 j ∘SL 𝐩 l - 𝐱 l ∘SL 𝐩 j) - δ[i,l] • (𝐱 j ∘SL 𝐩 k - 𝐱 k ∘SL 𝐩 j) - δ[j,k] • (𝐱 i ∘SL 𝐩 l - 𝐱 l ∘SL 𝐩 i) + δ[j,l] • (𝐱 i ∘SL 𝐩 k - 𝐱 k ∘SL 𝐩 i)) d:ℕi:Fin dj:Fin dk:Fin dl:Fin dx✝¹:𝓢(Space d, ℂ)x✝:Space d⊢ (((I * ↑↑ℏ) • (δ[i,l] • 𝐱 k ∘SL 𝐩 j - δ[j,l] • 𝐱 k ∘SL 𝐩 i + (δ[i,k] • 𝐱 j ∘SL 𝐩 l - δ[j,k] • 𝐱 i ∘SL 𝐩 l) - (δ[i,k] • 𝐱 l ∘SL 𝐩 j - δ[j,k] • 𝐱 l ∘SL 𝐩 i + (δ[i,l] • 𝐱 j ∘SL 𝐩 k - δ[j,l] • 𝐱 i ∘SL 𝐩 k)))) x✝¹) x✝ = (((I * ↑↑ℏ) • (δ[i,k] • (𝐱 j ∘SL 𝐩 l - 𝐱 l ∘SL 𝐩 j) - δ[i,l] • (𝐱 j ∘SL 𝐩 k - 𝐱 k ∘SL 𝐩 j) - δ[j,k] • (𝐱 i ∘SL 𝐩 l - 𝐱 l ∘SL 𝐩 i) + δ[j,l] • (𝐱 i ∘SL 𝐩 k - 𝐱 k ∘SL 𝐩 i))) x✝¹) x✝ d:ℕi:Fin dj:Fin dk:Fin dl:Fin dx✝¹:𝓢(Space d, ℂ)x✝:Space d⊢ I * ↑↑ℏ * (-(↑δ[i,l] * (↑(x✝.val k) * (I * ↑↑ℏ * Space.deriv j (⇑x✝¹) x✝))) + ↑δ[j,l] * (↑(x✝.val k) * (I * ↑↑ℏ * Space.deriv i (⇑x✝¹) x✝)) + (-(↑δ[i,k] * (↑(x✝.val j) * (I * ↑↑ℏ * Space.deriv l (⇑x✝¹) x✝))) + ↑δ[j,k] * (↑(x✝.val i) * (I * ↑↑ℏ * Space.deriv l (⇑x✝¹) x✝))) - (-(↑δ[i,k] * (↑(x✝.val l) * (I * ↑↑ℏ * Space.deriv j (⇑x✝¹) x✝))) + ↑δ[j,k] * (↑(x✝.val l) * (I * ↑↑ℏ * Space.deriv i (⇑x✝¹) x✝)) + (-(↑δ[i,l] * (↑(x✝.val j) * (I * ↑↑ℏ * Space.deriv k (⇑x✝¹) x✝))) + ↑δ[j,l] * (↑(x✝.val i) * (I * ↑↑ℏ * Space.deriv k (⇑x✝¹) x✝))))) = I * ↑↑ℏ * (-(↑δ[i,k] * (↑(x✝.val j) * (I * ↑↑ℏ * Space.deriv l (⇑x✝¹) x✝))) + ↑δ[i,k] * (↑(x✝.val l) * (I * ↑↑ℏ * Space.deriv j (⇑x✝¹) x✝)) - (-(↑δ[i,l] * (↑(x✝.val j) * (I * ↑↑ℏ * Space.deriv k (⇑x✝¹) x✝))) + ↑δ[i,l] * (↑(x✝.val k) * (I * ↑↑ℏ * Space.deriv j (⇑x✝¹) x✝))) - (-(↑δ[j,k] * (↑(x✝.val i) * (I * ↑↑ℏ * Space.deriv l (⇑x✝¹) x✝))) + ↑δ[j,k] * (↑(x✝.val l) * (I * ↑↑ℏ * Space.deriv i (⇑x✝¹) x✝)))) + I * ↑↑ℏ * (-(↑δ[j,l] * (↑(x✝.val i) * (I * ↑↑ℏ * Space.deriv k (⇑x✝¹) x✝))) + ↑δ[j,l] * (↑(x✝.val k) * (I * ↑↑ℏ * Space.deriv i (⇑x✝¹) x✝))) All goals completed! 🐙@[simp] lemma angularMomentumSqr_commutation_angularMomentum : ⁅𝐋²[d], 𝐋 i j⁆ = 0 := d:ℕi:Fin dj:Fin d⊢ ⁅𝐋², 𝐋 i j⁆ = 0 d:ℕi:Fin dj:Fin d⊢ 2⁻¹ • (I * ↑↑ℏ) • (∑ x, 𝐋 i x ∘SL 𝐋 x j - ∑ x, (-𝐋 x j) ∘SL (-𝐋 i x) - ∑ x, (-𝐋 i x) ∘SL 𝐋 x j + ∑ x, 𝐋 x j ∘SL (-𝐋 i x) + (∑ x, 𝐋 x j ∘SL 𝐋 i x - ∑ x, (-𝐋 i x) ∘SL (-𝐋 x j) - ∑ x, 𝐋 x j ∘SL (-𝐋 i x) + ∑ x, (-𝐋 i x) ∘SL 𝐋 x j)) = 0 d:ℕi:Fin dj:Fin d⊢ 2⁻¹ • (I * ↑↑ℏ) • (∑ x, 𝐋 i x ∘SL 𝐋 x j + (-1 • ∑ x, (-1 • 𝐋 x j) ∘SL (-1 • 𝐋 i x) + (∑ x, 𝐋 x j ∘SL 𝐋 i x + -1 • ∑ x, (-1 • 𝐋 i x) ∘SL (-1 • 𝐋 x j)))) = 0 All goals completed! 🐙