Proof of Theorem mhmlem
| Step | Hyp | Ref | Expression | 
|---|
| 1 |  | id 22 | . 2
⊢ (𝜑 → 𝜑) | 
| 2 |  | mhmlem.a | . 2
⊢ (𝜑 → 𝐴 ∈ 𝑋) | 
| 3 |  | mhmlem.b | . 2
⊢ (𝜑 → 𝐵 ∈ 𝑋) | 
| 4 |  | eleq1 2828 | . . . . . 6
⊢ (𝑥 = 𝐴 → (𝑥 ∈ 𝑋 ↔ 𝐴 ∈ 𝑋)) | 
| 5 | 4 | 3anbi2d 1442 | . . . . 5
⊢ (𝑥 = 𝐴 → ((𝜑 ∧ 𝑥 ∈ 𝑋 ∧ 𝑦 ∈ 𝑋) ↔ (𝜑 ∧ 𝐴 ∈ 𝑋 ∧ 𝑦 ∈ 𝑋))) | 
| 6 |  | fvoveq1 7455 | . . . . . 6
⊢ (𝑥 = 𝐴 → (𝐹‘(𝑥 + 𝑦)) = (𝐹‘(𝐴 + 𝑦))) | 
| 7 |  | fveq2 6905 | . . . . . . 7
⊢ (𝑥 = 𝐴 → (𝐹‘𝑥) = (𝐹‘𝐴)) | 
| 8 | 7 | oveq1d 7447 | . . . . . 6
⊢ (𝑥 = 𝐴 → ((𝐹‘𝑥) ⨣ (𝐹‘𝑦)) = ((𝐹‘𝐴) ⨣ (𝐹‘𝑦))) | 
| 9 | 6, 8 | eqeq12d 2752 | . . . . 5
⊢ (𝑥 = 𝐴 → ((𝐹‘(𝑥 + 𝑦)) = ((𝐹‘𝑥) ⨣ (𝐹‘𝑦)) ↔ (𝐹‘(𝐴 + 𝑦)) = ((𝐹‘𝐴) ⨣ (𝐹‘𝑦)))) | 
| 10 | 5, 9 | imbi12d 344 | . . . 4
⊢ (𝑥 = 𝐴 → (((𝜑 ∧ 𝑥 ∈ 𝑋 ∧ 𝑦 ∈ 𝑋) → (𝐹‘(𝑥 + 𝑦)) = ((𝐹‘𝑥) ⨣ (𝐹‘𝑦))) ↔ ((𝜑 ∧ 𝐴 ∈ 𝑋 ∧ 𝑦 ∈ 𝑋) → (𝐹‘(𝐴 + 𝑦)) = ((𝐹‘𝐴) ⨣ (𝐹‘𝑦))))) | 
| 11 |  | eleq1 2828 | . . . . . 6
⊢ (𝑦 = 𝐵 → (𝑦 ∈ 𝑋 ↔ 𝐵 ∈ 𝑋)) | 
| 12 | 11 | 3anbi3d 1443 | . . . . 5
⊢ (𝑦 = 𝐵 → ((𝜑 ∧ 𝐴 ∈ 𝑋 ∧ 𝑦 ∈ 𝑋) ↔ (𝜑 ∧ 𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋))) | 
| 13 |  | oveq2 7440 | . . . . . . 7
⊢ (𝑦 = 𝐵 → (𝐴 + 𝑦) = (𝐴 + 𝐵)) | 
| 14 | 13 | fveq2d 6909 | . . . . . 6
⊢ (𝑦 = 𝐵 → (𝐹‘(𝐴 + 𝑦)) = (𝐹‘(𝐴 + 𝐵))) | 
| 15 |  | fveq2 6905 | . . . . . . 7
⊢ (𝑦 = 𝐵 → (𝐹‘𝑦) = (𝐹‘𝐵)) | 
| 16 | 15 | oveq2d 7448 | . . . . . 6
⊢ (𝑦 = 𝐵 → ((𝐹‘𝐴) ⨣ (𝐹‘𝑦)) = ((𝐹‘𝐴) ⨣ (𝐹‘𝐵))) | 
| 17 | 14, 16 | eqeq12d 2752 | . . . . 5
⊢ (𝑦 = 𝐵 → ((𝐹‘(𝐴 + 𝑦)) = ((𝐹‘𝐴) ⨣ (𝐹‘𝑦)) ↔ (𝐹‘(𝐴 + 𝐵)) = ((𝐹‘𝐴) ⨣ (𝐹‘𝐵)))) | 
| 18 | 12, 17 | imbi12d 344 | . . . 4
⊢ (𝑦 = 𝐵 → (((𝜑 ∧ 𝐴 ∈ 𝑋 ∧ 𝑦 ∈ 𝑋) → (𝐹‘(𝐴 + 𝑦)) = ((𝐹‘𝐴) ⨣ (𝐹‘𝑦))) ↔ ((𝜑 ∧ 𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋) → (𝐹‘(𝐴 + 𝐵)) = ((𝐹‘𝐴) ⨣ (𝐹‘𝐵))))) | 
| 19 |  | ghmgrp.f | . . . 4
⊢ ((𝜑 ∧ 𝑥 ∈ 𝑋 ∧ 𝑦 ∈ 𝑋) → (𝐹‘(𝑥 + 𝑦)) = ((𝐹‘𝑥) ⨣ (𝐹‘𝑦))) | 
| 20 | 10, 18, 19 | vtocl2g 3573 | . . 3
⊢ ((𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋) → ((𝜑 ∧ 𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋) → (𝐹‘(𝐴 + 𝐵)) = ((𝐹‘𝐴) ⨣ (𝐹‘𝐵)))) | 
| 21 | 2, 3, 20 | syl2anc 584 | . 2
⊢ (𝜑 → ((𝜑 ∧ 𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋) → (𝐹‘(𝐴 + 𝐵)) = ((𝐹‘𝐴) ⨣ (𝐹‘𝐵)))) | 
| 22 | 1, 2, 3, 21 | mp3and 1465 | 1
⊢ (𝜑 → (𝐹‘(𝐴 + 𝐵)) = ((𝐹‘𝐴) ⨣ (𝐹‘𝐵))) |