| Step | Hyp | Ref
 | Expression | 
| 1 |   | anandi 590 | 
. . . 4
⊢ ((𝑓 Fn 𝐴 ∧ (∀𝑥 ∈ 𝐴 (𝑓‘𝑥) ∈ 𝐵 ∧ ∀𝑥 ∈ 𝐴 (𝑓‘𝑥) ∈ 𝐶)) ↔ ((𝑓 Fn 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝑓‘𝑥) ∈ 𝐵) ∧ (𝑓 Fn 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝑓‘𝑥) ∈ 𝐶))) | 
| 2 |   | elin 3346 | 
. . . . . . 7
⊢ ((𝑓‘𝑥) ∈ (𝐵 ∩ 𝐶) ↔ ((𝑓‘𝑥) ∈ 𝐵 ∧ (𝑓‘𝑥) ∈ 𝐶)) | 
| 3 | 2 | ralbii 2503 | 
. . . . . 6
⊢
(∀𝑥 ∈
𝐴 (𝑓‘𝑥) ∈ (𝐵 ∩ 𝐶) ↔ ∀𝑥 ∈ 𝐴 ((𝑓‘𝑥) ∈ 𝐵 ∧ (𝑓‘𝑥) ∈ 𝐶)) | 
| 4 |   | r19.26 2623 | 
. . . . . 6
⊢
(∀𝑥 ∈
𝐴 ((𝑓‘𝑥) ∈ 𝐵 ∧ (𝑓‘𝑥) ∈ 𝐶) ↔ (∀𝑥 ∈ 𝐴 (𝑓‘𝑥) ∈ 𝐵 ∧ ∀𝑥 ∈ 𝐴 (𝑓‘𝑥) ∈ 𝐶)) | 
| 5 | 3, 4 | bitri 184 | 
. . . . 5
⊢
(∀𝑥 ∈
𝐴 (𝑓‘𝑥) ∈ (𝐵 ∩ 𝐶) ↔ (∀𝑥 ∈ 𝐴 (𝑓‘𝑥) ∈ 𝐵 ∧ ∀𝑥 ∈ 𝐴 (𝑓‘𝑥) ∈ 𝐶)) | 
| 6 | 5 | anbi2i 457 | 
. . . 4
⊢ ((𝑓 Fn 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝑓‘𝑥) ∈ (𝐵 ∩ 𝐶)) ↔ (𝑓 Fn 𝐴 ∧ (∀𝑥 ∈ 𝐴 (𝑓‘𝑥) ∈ 𝐵 ∧ ∀𝑥 ∈ 𝐴 (𝑓‘𝑥) ∈ 𝐶))) | 
| 7 |   | vex 2766 | 
. . . . . 6
⊢ 𝑓 ∈ V | 
| 8 | 7 | elixp 6764 | 
. . . . 5
⊢ (𝑓 ∈ X𝑥 ∈
𝐴 𝐵 ↔ (𝑓 Fn 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝑓‘𝑥) ∈ 𝐵)) | 
| 9 | 7 | elixp 6764 | 
. . . . 5
⊢ (𝑓 ∈ X𝑥 ∈
𝐴 𝐶 ↔ (𝑓 Fn 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝑓‘𝑥) ∈ 𝐶)) | 
| 10 | 8, 9 | anbi12i 460 | 
. . . 4
⊢ ((𝑓 ∈ X𝑥 ∈
𝐴 𝐵 ∧ 𝑓 ∈ X𝑥 ∈ 𝐴 𝐶) ↔ ((𝑓 Fn 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝑓‘𝑥) ∈ 𝐵) ∧ (𝑓 Fn 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝑓‘𝑥) ∈ 𝐶))) | 
| 11 | 1, 6, 10 | 3bitr4i 212 | 
. . 3
⊢ ((𝑓 Fn 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝑓‘𝑥) ∈ (𝐵 ∩ 𝐶)) ↔ (𝑓 ∈ X𝑥 ∈ 𝐴 𝐵 ∧ 𝑓 ∈ X𝑥 ∈ 𝐴 𝐶)) | 
| 12 | 7 | elixp 6764 | 
. . 3
⊢ (𝑓 ∈ X𝑥 ∈
𝐴 (𝐵 ∩ 𝐶) ↔ (𝑓 Fn 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝑓‘𝑥) ∈ (𝐵 ∩ 𝐶))) | 
| 13 |   | elin 3346 | 
. . 3
⊢ (𝑓 ∈ (X𝑥 ∈
𝐴 𝐵 ∩ X𝑥 ∈ 𝐴 𝐶) ↔ (𝑓 ∈ X𝑥 ∈ 𝐴 𝐵 ∧ 𝑓 ∈ X𝑥 ∈ 𝐴 𝐶)) | 
| 14 | 11, 12, 13 | 3bitr4i 212 | 
. 2
⊢ (𝑓 ∈ X𝑥 ∈
𝐴 (𝐵 ∩ 𝐶) ↔ 𝑓 ∈ (X𝑥 ∈ 𝐴 𝐵 ∩ X𝑥 ∈ 𝐴 𝐶)) | 
| 15 | 14 | eqriv 2193 | 
1
⊢ X𝑥 ∈
𝐴 (𝐵 ∩ 𝐶) = (X𝑥 ∈ 𝐴 𝐵 ∩ X𝑥 ∈ 𝐴 𝐶) |