| Step | Hyp | Ref | Expression | 
|---|
| 1 |  | caonncan.a | . . . . 5
⊢ (𝜑 → 𝐴:𝐼⟶𝑆) | 
| 2 | 1 | ffvelcdmda 7104 | . . . 4
⊢ ((𝜑 ∧ 𝑧 ∈ 𝐼) → (𝐴‘𝑧) ∈ 𝑆) | 
| 3 |  | caonncan.b | . . . . 5
⊢ (𝜑 → 𝐵:𝐼⟶𝑆) | 
| 4 | 3 | ffvelcdmda 7104 | . . . 4
⊢ ((𝜑 ∧ 𝑧 ∈ 𝐼) → (𝐵‘𝑧) ∈ 𝑆) | 
| 5 |  | caonncan.z | . . . . . 6
⊢ ((𝜑 ∧ (𝑥 ∈ 𝑆 ∧ 𝑦 ∈ 𝑆)) → (𝑥𝑀(𝑥𝑀𝑦)) = 𝑦) | 
| 6 | 5 | ralrimivva 3202 | . . . . 5
⊢ (𝜑 → ∀𝑥 ∈ 𝑆 ∀𝑦 ∈ 𝑆 (𝑥𝑀(𝑥𝑀𝑦)) = 𝑦) | 
| 7 | 6 | adantr 480 | . . . 4
⊢ ((𝜑 ∧ 𝑧 ∈ 𝐼) → ∀𝑥 ∈ 𝑆 ∀𝑦 ∈ 𝑆 (𝑥𝑀(𝑥𝑀𝑦)) = 𝑦) | 
| 8 |  | id 22 | . . . . . . 7
⊢ (𝑥 = (𝐴‘𝑧) → 𝑥 = (𝐴‘𝑧)) | 
| 9 |  | oveq1 7438 | . . . . . . 7
⊢ (𝑥 = (𝐴‘𝑧) → (𝑥𝑀𝑦) = ((𝐴‘𝑧)𝑀𝑦)) | 
| 10 | 8, 9 | oveq12d 7449 | . . . . . 6
⊢ (𝑥 = (𝐴‘𝑧) → (𝑥𝑀(𝑥𝑀𝑦)) = ((𝐴‘𝑧)𝑀((𝐴‘𝑧)𝑀𝑦))) | 
| 11 | 10 | eqeq1d 2739 | . . . . 5
⊢ (𝑥 = (𝐴‘𝑧) → ((𝑥𝑀(𝑥𝑀𝑦)) = 𝑦 ↔ ((𝐴‘𝑧)𝑀((𝐴‘𝑧)𝑀𝑦)) = 𝑦)) | 
| 12 |  | oveq2 7439 | . . . . . . 7
⊢ (𝑦 = (𝐵‘𝑧) → ((𝐴‘𝑧)𝑀𝑦) = ((𝐴‘𝑧)𝑀(𝐵‘𝑧))) | 
| 13 | 12 | oveq2d 7447 | . . . . . 6
⊢ (𝑦 = (𝐵‘𝑧) → ((𝐴‘𝑧)𝑀((𝐴‘𝑧)𝑀𝑦)) = ((𝐴‘𝑧)𝑀((𝐴‘𝑧)𝑀(𝐵‘𝑧)))) | 
| 14 |  | id 22 | . . . . . 6
⊢ (𝑦 = (𝐵‘𝑧) → 𝑦 = (𝐵‘𝑧)) | 
| 15 | 13, 14 | eqeq12d 2753 | . . . . 5
⊢ (𝑦 = (𝐵‘𝑧) → (((𝐴‘𝑧)𝑀((𝐴‘𝑧)𝑀𝑦)) = 𝑦 ↔ ((𝐴‘𝑧)𝑀((𝐴‘𝑧)𝑀(𝐵‘𝑧))) = (𝐵‘𝑧))) | 
| 16 | 11, 15 | rspc2va 3634 | . . . 4
⊢ ((((𝐴‘𝑧) ∈ 𝑆 ∧ (𝐵‘𝑧) ∈ 𝑆) ∧ ∀𝑥 ∈ 𝑆 ∀𝑦 ∈ 𝑆 (𝑥𝑀(𝑥𝑀𝑦)) = 𝑦) → ((𝐴‘𝑧)𝑀((𝐴‘𝑧)𝑀(𝐵‘𝑧))) = (𝐵‘𝑧)) | 
| 17 | 2, 4, 7, 16 | syl21anc 838 | . . 3
⊢ ((𝜑 ∧ 𝑧 ∈ 𝐼) → ((𝐴‘𝑧)𝑀((𝐴‘𝑧)𝑀(𝐵‘𝑧))) = (𝐵‘𝑧)) | 
| 18 | 17 | mpteq2dva 5242 | . 2
⊢ (𝜑 → (𝑧 ∈ 𝐼 ↦ ((𝐴‘𝑧)𝑀((𝐴‘𝑧)𝑀(𝐵‘𝑧)))) = (𝑧 ∈ 𝐼 ↦ (𝐵‘𝑧))) | 
| 19 |  | caonncan.i | . . 3
⊢ (𝜑 → 𝐼 ∈ 𝑉) | 
| 20 |  | fvexd 6921 | . . 3
⊢ ((𝜑 ∧ 𝑧 ∈ 𝐼) → (𝐴‘𝑧) ∈ V) | 
| 21 |  | ovexd 7466 | . . 3
⊢ ((𝜑 ∧ 𝑧 ∈ 𝐼) → ((𝐴‘𝑧)𝑀(𝐵‘𝑧)) ∈ V) | 
| 22 | 1 | feqmptd 6977 | . . 3
⊢ (𝜑 → 𝐴 = (𝑧 ∈ 𝐼 ↦ (𝐴‘𝑧))) | 
| 23 |  | fvexd 6921 | . . . 4
⊢ ((𝜑 ∧ 𝑧 ∈ 𝐼) → (𝐵‘𝑧) ∈ V) | 
| 24 | 3 | feqmptd 6977 | . . . 4
⊢ (𝜑 → 𝐵 = (𝑧 ∈ 𝐼 ↦ (𝐵‘𝑧))) | 
| 25 | 19, 20, 23, 22, 24 | offval2 7717 | . . 3
⊢ (𝜑 → (𝐴 ∘f 𝑀𝐵) = (𝑧 ∈ 𝐼 ↦ ((𝐴‘𝑧)𝑀(𝐵‘𝑧)))) | 
| 26 | 19, 20, 21, 22, 25 | offval2 7717 | . 2
⊢ (𝜑 → (𝐴 ∘f 𝑀(𝐴 ∘f 𝑀𝐵)) = (𝑧 ∈ 𝐼 ↦ ((𝐴‘𝑧)𝑀((𝐴‘𝑧)𝑀(𝐵‘𝑧))))) | 
| 27 | 18, 26, 24 | 3eqtr4d 2787 | 1
⊢ (𝜑 → (𝐴 ∘f 𝑀(𝐴 ∘f 𝑀𝐵)) = 𝐵) |