Proof of Theorem elpreima
| Step | Hyp | Ref
| Expression |
| 1 | | cnvimass 6075 |
. . . . 5
⊢ (◡𝐹 “ 𝐶) ⊆ dom 𝐹 |
| 2 | 1 | sseli 3935 |
. . . 4
⊢ (𝐵 ∈ (◡𝐹 “ 𝐶) → 𝐵 ∈ dom 𝐹) |
| 3 | | fndm 6628 |
. . . . 5
⊢ (𝐹 Fn 𝐴 → dom 𝐹 = 𝐴) |
| 4 | 3 | eleq2d 2851 |
. . . 4
⊢ (𝐹 Fn 𝐴 → (𝐵 ∈ dom 𝐹 ↔ 𝐵 ∈ 𝐴)) |
| 5 | 2, 4 | imbitrid 247 |
. . 3
⊢ (𝐹 Fn 𝐴 → (𝐵 ∈ (◡𝐹 “ 𝐶) → 𝐵 ∈ 𝐴)) |
| 6 | | fnfun 6625 |
. . . . 5
⊢ (𝐹 Fn 𝐴 → Fun 𝐹) |
| 7 | | fvimacnvi 7037 |
. . . . 5
⊢ ((Fun
𝐹 ∧ 𝐵 ∈ (◡𝐹 “ 𝐶)) → (𝐹‘𝐵) ∈ 𝐶) |
| 8 | 6, 7 | sylan 591 |
. . . 4
⊢ ((𝐹 Fn 𝐴 ∧ 𝐵 ∈ (◡𝐹 “ 𝐶)) → (𝐹‘𝐵) ∈ 𝐶) |
| 9 | 8 | ex 417 |
. . 3
⊢ (𝐹 Fn 𝐴 → (𝐵 ∈ (◡𝐹 “ 𝐶) → (𝐹‘𝐵) ∈ 𝐶)) |
| 10 | 5, 9 | jcad 521 |
. 2
⊢ (𝐹 Fn 𝐴 → (𝐵 ∈ (◡𝐹 “ 𝐶) → (𝐵 ∈ 𝐴 ∧ (𝐹‘𝐵) ∈ 𝐶))) |
| 11 | | fvimacnv 7038 |
. . . . 5
⊢ ((Fun
𝐹 ∧ 𝐵 ∈ dom 𝐹) → ((𝐹‘𝐵) ∈ 𝐶 ↔ 𝐵 ∈ (◡𝐹 “ 𝐶))) |
| 12 | 11 | funfni 6631 |
. . . 4
⊢ ((𝐹 Fn 𝐴 ∧ 𝐵 ∈ 𝐴) → ((𝐹‘𝐵) ∈ 𝐶 ↔ 𝐵 ∈ (◡𝐹 “ 𝐶))) |
| 13 | 12 | biimpd 232 |
. . 3
⊢ ((𝐹 Fn 𝐴 ∧ 𝐵 ∈ 𝐴) → ((𝐹‘𝐵) ∈ 𝐶 → 𝐵 ∈ (◡𝐹 “ 𝐶))) |
| 14 | 13 | expimpd 458 |
. 2
⊢ (𝐹 Fn 𝐴 → ((𝐵 ∈ 𝐴 ∧ (𝐹‘𝐵) ∈ 𝐶) → 𝐵 ∈ (◡𝐹 “ 𝐶))) |
| 15 | 10, 14 | impbid 215 |
1
⊢ (𝐹 Fn 𝐴 → (𝐵 ∈ (◡𝐹 “ 𝐶) ↔ (𝐵 ∈ 𝐴 ∧ (𝐹‘𝐵) ∈ 𝐶))) |