| Step | Hyp | Ref | Expression | 
|---|
| 1 |  | simp2 1137 | . . . . . . . 8
⊢ ((𝐴 ∈ 𝑉 ∧ 𝐹:𝐴⟶ℂ ∧ 𝐺:𝐴⟶ℂ) → 𝐹:𝐴⟶ℂ) | 
| 2 | 1 | ffnd 6736 | . . . . . . 7
⊢ ((𝐴 ∈ 𝑉 ∧ 𝐹:𝐴⟶ℂ ∧ 𝐺:𝐴⟶ℂ) → 𝐹 Fn 𝐴) | 
| 3 |  | simp3 1138 | . . . . . . . 8
⊢ ((𝐴 ∈ 𝑉 ∧ 𝐹:𝐴⟶ℂ ∧ 𝐺:𝐴⟶ℂ) → 𝐺:𝐴⟶ℂ) | 
| 4 | 3 | ffnd 6736 | . . . . . . 7
⊢ ((𝐴 ∈ 𝑉 ∧ 𝐹:𝐴⟶ℂ ∧ 𝐺:𝐴⟶ℂ) → 𝐺 Fn 𝐴) | 
| 5 |  | simp1 1136 | . . . . . . 7
⊢ ((𝐴 ∈ 𝑉 ∧ 𝐹:𝐴⟶ℂ ∧ 𝐺:𝐴⟶ℂ) → 𝐴 ∈ 𝑉) | 
| 6 |  | inidm 4226 | . . . . . . 7
⊢ (𝐴 ∩ 𝐴) = 𝐴 | 
| 7 |  | eqidd 2737 | . . . . . . 7
⊢ (((𝐴 ∈ 𝑉 ∧ 𝐹:𝐴⟶ℂ ∧ 𝐺:𝐴⟶ℂ) ∧ 𝑥 ∈ 𝐴) → (𝐹‘𝑥) = (𝐹‘𝑥)) | 
| 8 |  | eqidd 2737 | . . . . . . 7
⊢ (((𝐴 ∈ 𝑉 ∧ 𝐹:𝐴⟶ℂ ∧ 𝐺:𝐴⟶ℂ) ∧ 𝑥 ∈ 𝐴) → (𝐺‘𝑥) = (𝐺‘𝑥)) | 
| 9 | 2, 4, 5, 5, 6, 7, 8 | ofval 7709 | . . . . . 6
⊢ (((𝐴 ∈ 𝑉 ∧ 𝐹:𝐴⟶ℂ ∧ 𝐺:𝐴⟶ℂ) ∧ 𝑥 ∈ 𝐴) → ((𝐹 ∘f · 𝐺)‘𝑥) = ((𝐹‘𝑥) · (𝐺‘𝑥))) | 
| 10 | 9 | eqeq1d 2738 | . . . . 5
⊢ (((𝐴 ∈ 𝑉 ∧ 𝐹:𝐴⟶ℂ ∧ 𝐺:𝐴⟶ℂ) ∧ 𝑥 ∈ 𝐴) → (((𝐹 ∘f · 𝐺)‘𝑥) = 0 ↔ ((𝐹‘𝑥) · (𝐺‘𝑥)) = 0)) | 
| 11 | 1 | ffvelcdmda 7103 | . . . . . 6
⊢ (((𝐴 ∈ 𝑉 ∧ 𝐹:𝐴⟶ℂ ∧ 𝐺:𝐴⟶ℂ) ∧ 𝑥 ∈ 𝐴) → (𝐹‘𝑥) ∈ ℂ) | 
| 12 | 3 | ffvelcdmda 7103 | . . . . . 6
⊢ (((𝐴 ∈ 𝑉 ∧ 𝐹:𝐴⟶ℂ ∧ 𝐺:𝐴⟶ℂ) ∧ 𝑥 ∈ 𝐴) → (𝐺‘𝑥) ∈ ℂ) | 
| 13 | 11, 12 | mul0ord 11914 | . . . . 5
⊢ (((𝐴 ∈ 𝑉 ∧ 𝐹:𝐴⟶ℂ ∧ 𝐺:𝐴⟶ℂ) ∧ 𝑥 ∈ 𝐴) → (((𝐹‘𝑥) · (𝐺‘𝑥)) = 0 ↔ ((𝐹‘𝑥) = 0 ∨ (𝐺‘𝑥) = 0))) | 
| 14 | 10, 13 | bitrd 279 | . . . 4
⊢ (((𝐴 ∈ 𝑉 ∧ 𝐹:𝐴⟶ℂ ∧ 𝐺:𝐴⟶ℂ) ∧ 𝑥 ∈ 𝐴) → (((𝐹 ∘f · 𝐺)‘𝑥) = 0 ↔ ((𝐹‘𝑥) = 0 ∨ (𝐺‘𝑥) = 0))) | 
| 15 | 14 | pm5.32da 579 | . . 3
⊢ ((𝐴 ∈ 𝑉 ∧ 𝐹:𝐴⟶ℂ ∧ 𝐺:𝐴⟶ℂ) → ((𝑥 ∈ 𝐴 ∧ ((𝐹 ∘f · 𝐺)‘𝑥) = 0) ↔ (𝑥 ∈ 𝐴 ∧ ((𝐹‘𝑥) = 0 ∨ (𝐺‘𝑥) = 0)))) | 
| 16 | 2, 4, 5, 5, 6 | offn 7711 | . . . 4
⊢ ((𝐴 ∈ 𝑉 ∧ 𝐹:𝐴⟶ℂ ∧ 𝐺:𝐴⟶ℂ) → (𝐹 ∘f · 𝐺) Fn 𝐴) | 
| 17 |  | fniniseg 7079 | . . . 4
⊢ ((𝐹 ∘f ·
𝐺) Fn 𝐴 → (𝑥 ∈ (◡(𝐹 ∘f · 𝐺) “ {0}) ↔ (𝑥 ∈ 𝐴 ∧ ((𝐹 ∘f · 𝐺)‘𝑥) = 0))) | 
| 18 | 16, 17 | syl 17 | . . 3
⊢ ((𝐴 ∈ 𝑉 ∧ 𝐹:𝐴⟶ℂ ∧ 𝐺:𝐴⟶ℂ) → (𝑥 ∈ (◡(𝐹 ∘f · 𝐺) “ {0}) ↔ (𝑥 ∈ 𝐴 ∧ ((𝐹 ∘f · 𝐺)‘𝑥) = 0))) | 
| 19 |  | fniniseg 7079 | . . . . . 6
⊢ (𝐹 Fn 𝐴 → (𝑥 ∈ (◡𝐹 “ {0}) ↔ (𝑥 ∈ 𝐴 ∧ (𝐹‘𝑥) = 0))) | 
| 20 | 2, 19 | syl 17 | . . . . 5
⊢ ((𝐴 ∈ 𝑉 ∧ 𝐹:𝐴⟶ℂ ∧ 𝐺:𝐴⟶ℂ) → (𝑥 ∈ (◡𝐹 “ {0}) ↔ (𝑥 ∈ 𝐴 ∧ (𝐹‘𝑥) = 0))) | 
| 21 |  | fniniseg 7079 | . . . . . 6
⊢ (𝐺 Fn 𝐴 → (𝑥 ∈ (◡𝐺 “ {0}) ↔ (𝑥 ∈ 𝐴 ∧ (𝐺‘𝑥) = 0))) | 
| 22 | 4, 21 | syl 17 | . . . . 5
⊢ ((𝐴 ∈ 𝑉 ∧ 𝐹:𝐴⟶ℂ ∧ 𝐺:𝐴⟶ℂ) → (𝑥 ∈ (◡𝐺 “ {0}) ↔ (𝑥 ∈ 𝐴 ∧ (𝐺‘𝑥) = 0))) | 
| 23 | 20, 22 | orbi12d 918 | . . . 4
⊢ ((𝐴 ∈ 𝑉 ∧ 𝐹:𝐴⟶ℂ ∧ 𝐺:𝐴⟶ℂ) → ((𝑥 ∈ (◡𝐹 “ {0}) ∨ 𝑥 ∈ (◡𝐺 “ {0})) ↔ ((𝑥 ∈ 𝐴 ∧ (𝐹‘𝑥) = 0) ∨ (𝑥 ∈ 𝐴 ∧ (𝐺‘𝑥) = 0)))) | 
| 24 |  | elun 4152 | . . . 4
⊢ (𝑥 ∈ ((◡𝐹 “ {0}) ∪ (◡𝐺 “ {0})) ↔ (𝑥 ∈ (◡𝐹 “ {0}) ∨ 𝑥 ∈ (◡𝐺 “ {0}))) | 
| 25 |  | andi 1009 | . . . 4
⊢ ((𝑥 ∈ 𝐴 ∧ ((𝐹‘𝑥) = 0 ∨ (𝐺‘𝑥) = 0)) ↔ ((𝑥 ∈ 𝐴 ∧ (𝐹‘𝑥) = 0) ∨ (𝑥 ∈ 𝐴 ∧ (𝐺‘𝑥) = 0))) | 
| 26 | 23, 24, 25 | 3bitr4g 314 | . . 3
⊢ ((𝐴 ∈ 𝑉 ∧ 𝐹:𝐴⟶ℂ ∧ 𝐺:𝐴⟶ℂ) → (𝑥 ∈ ((◡𝐹 “ {0}) ∪ (◡𝐺 “ {0})) ↔ (𝑥 ∈ 𝐴 ∧ ((𝐹‘𝑥) = 0 ∨ (𝐺‘𝑥) = 0)))) | 
| 27 | 15, 18, 26 | 3bitr4d 311 | . 2
⊢ ((𝐴 ∈ 𝑉 ∧ 𝐹:𝐴⟶ℂ ∧ 𝐺:𝐴⟶ℂ) → (𝑥 ∈ (◡(𝐹 ∘f · 𝐺) “ {0}) ↔ 𝑥 ∈ ((◡𝐹 “ {0}) ∪ (◡𝐺 “ {0})))) | 
| 28 | 27 | eqrdv 2734 | 1
⊢ ((𝐴 ∈ 𝑉 ∧ 𝐹:𝐴⟶ℂ ∧ 𝐺:𝐴⟶ℂ) → (◡(𝐹 ∘f · 𝐺) “ {0}) = ((◡𝐹 “ {0}) ∪ (◡𝐺 “ {0}))) |