| Step | Hyp | Ref
| Expression |
| 1 | | fnrnfv 6967 |
. . 3
⊢ (𝐹 Fn 𝐴 → ran 𝐹 = {𝑦 ∣ ∃𝑥 ∈ 𝐴 𝑦 = (𝐹‘𝑥)}) |
| 2 | 1 | eleq2d 2826 |
. 2
⊢ (𝐹 Fn 𝐴 → (𝐵 ∈ ran 𝐹 ↔ 𝐵 ∈ {𝑦 ∣ ∃𝑥 ∈ 𝐴 𝑦 = (𝐹‘𝑥)})) |
| 3 | | fvex 6918 |
. . . . 5
⊢ (𝐹‘𝑥) ∈ V |
| 4 | | eleq1 2828 |
. . . . 5
⊢ ((𝐹‘𝑥) = 𝐵 → ((𝐹‘𝑥) ∈ V ↔ 𝐵 ∈ V)) |
| 5 | 3, 4 | mpbii 233 |
. . . 4
⊢ ((𝐹‘𝑥) = 𝐵 → 𝐵 ∈ V) |
| 6 | 5 | rexlimivw 3150 |
. . 3
⊢
(∃𝑥 ∈
𝐴 (𝐹‘𝑥) = 𝐵 → 𝐵 ∈ V) |
| 7 | | eqeq1 2740 |
. . . . 5
⊢ (𝑦 = 𝐵 → (𝑦 = (𝐹‘𝑥) ↔ 𝐵 = (𝐹‘𝑥))) |
| 8 | | eqcom 2743 |
. . . . 5
⊢ (𝐵 = (𝐹‘𝑥) ↔ (𝐹‘𝑥) = 𝐵) |
| 9 | 7, 8 | bitrdi 287 |
. . . 4
⊢ (𝑦 = 𝐵 → (𝑦 = (𝐹‘𝑥) ↔ (𝐹‘𝑥) = 𝐵)) |
| 10 | 9 | rexbidv 3178 |
. . 3
⊢ (𝑦 = 𝐵 → (∃𝑥 ∈ 𝐴 𝑦 = (𝐹‘𝑥) ↔ ∃𝑥 ∈ 𝐴 (𝐹‘𝑥) = 𝐵)) |
| 11 | 6, 10 | elab3 3685 |
. 2
⊢ (𝐵 ∈ {𝑦 ∣ ∃𝑥 ∈ 𝐴 𝑦 = (𝐹‘𝑥)} ↔ ∃𝑥 ∈ 𝐴 (𝐹‘𝑥) = 𝐵) |
| 12 | 2, 11 | bitrdi 287 |
1
⊢ (𝐹 Fn 𝐴 → (𝐵 ∈ ran 𝐹 ↔ ∃𝑥 ∈ 𝐴 (𝐹‘𝑥) = 𝐵)) |