Proof of Theorem f1omvdmvd
| Step | Hyp | Ref
| Expression |
| 1 | | simpr 477 |
. . . . 5
⊢ ((𝐹:𝐴–1-1-onto→𝐴 ∧ 𝑋 ∈ dom (𝐹 ∖ I )) → 𝑋 ∈ dom (𝐹 ∖ I )) |
| 2 | | f1ofn 6138 |
. . . . . . 7
⊢ (𝐹:𝐴–1-1-onto→𝐴 → 𝐹 Fn 𝐴) |
| 3 | 2 | adantr 481 |
. . . . . 6
⊢ ((𝐹:𝐴–1-1-onto→𝐴 ∧ 𝑋 ∈ dom (𝐹 ∖ I )) → 𝐹 Fn 𝐴) |
| 4 | | difss 3737 |
. . . . . . . . 9
⊢ (𝐹 ∖ I ) ⊆ 𝐹 |
| 5 | | dmss 5323 |
. . . . . . . . 9
⊢ ((𝐹 ∖ I ) ⊆ 𝐹 → dom (𝐹 ∖ I ) ⊆ dom 𝐹) |
| 6 | 4, 5 | ax-mp 5 |
. . . . . . . 8
⊢ dom
(𝐹 ∖ I ) ⊆ dom
𝐹 |
| 7 | | f1odm 6141 |
. . . . . . . 8
⊢ (𝐹:𝐴–1-1-onto→𝐴 → dom 𝐹 = 𝐴) |
| 8 | 6, 7 | syl5sseq 3653 |
. . . . . . 7
⊢ (𝐹:𝐴–1-1-onto→𝐴 → dom (𝐹 ∖ I ) ⊆ 𝐴) |
| 9 | 8 | sselda 3603 |
. . . . . 6
⊢ ((𝐹:𝐴–1-1-onto→𝐴 ∧ 𝑋 ∈ dom (𝐹 ∖ I )) → 𝑋 ∈ 𝐴) |
| 10 | | fnelnfp 6443 |
. . . . . 6
⊢ ((𝐹 Fn 𝐴 ∧ 𝑋 ∈ 𝐴) → (𝑋 ∈ dom (𝐹 ∖ I ) ↔ (𝐹‘𝑋) ≠ 𝑋)) |
| 11 | 3, 9, 10 | syl2anc 693 |
. . . . 5
⊢ ((𝐹:𝐴–1-1-onto→𝐴 ∧ 𝑋 ∈ dom (𝐹 ∖ I )) → (𝑋 ∈ dom (𝐹 ∖ I ) ↔ (𝐹‘𝑋) ≠ 𝑋)) |
| 12 | 1, 11 | mpbid 222 |
. . . 4
⊢ ((𝐹:𝐴–1-1-onto→𝐴 ∧ 𝑋 ∈ dom (𝐹 ∖ I )) → (𝐹‘𝑋) ≠ 𝑋) |
| 13 | | f1of1 6136 |
. . . . . . 7
⊢ (𝐹:𝐴–1-1-onto→𝐴 → 𝐹:𝐴–1-1→𝐴) |
| 14 | 13 | adantr 481 |
. . . . . 6
⊢ ((𝐹:𝐴–1-1-onto→𝐴 ∧ 𝑋 ∈ dom (𝐹 ∖ I )) → 𝐹:𝐴–1-1→𝐴) |
| 15 | | f1of 6137 |
. . . . . . . 8
⊢ (𝐹:𝐴–1-1-onto→𝐴 → 𝐹:𝐴⟶𝐴) |
| 16 | 15 | adantr 481 |
. . . . . . 7
⊢ ((𝐹:𝐴–1-1-onto→𝐴 ∧ 𝑋 ∈ dom (𝐹 ∖ I )) → 𝐹:𝐴⟶𝐴) |
| 17 | 16, 9 | ffvelrnd 6360 |
. . . . . 6
⊢ ((𝐹:𝐴–1-1-onto→𝐴 ∧ 𝑋 ∈ dom (𝐹 ∖ I )) → (𝐹‘𝑋) ∈ 𝐴) |
| 18 | | f1fveq 6519 |
. . . . . 6
⊢ ((𝐹:𝐴–1-1→𝐴 ∧ ((𝐹‘𝑋) ∈ 𝐴 ∧ 𝑋 ∈ 𝐴)) → ((𝐹‘(𝐹‘𝑋)) = (𝐹‘𝑋) ↔ (𝐹‘𝑋) = 𝑋)) |
| 19 | 14, 17, 9, 18 | syl12anc 1324 |
. . . . 5
⊢ ((𝐹:𝐴–1-1-onto→𝐴 ∧ 𝑋 ∈ dom (𝐹 ∖ I )) → ((𝐹‘(𝐹‘𝑋)) = (𝐹‘𝑋) ↔ (𝐹‘𝑋) = 𝑋)) |
| 20 | 19 | necon3bid 2838 |
. . . 4
⊢ ((𝐹:𝐴–1-1-onto→𝐴 ∧ 𝑋 ∈ dom (𝐹 ∖ I )) → ((𝐹‘(𝐹‘𝑋)) ≠ (𝐹‘𝑋) ↔ (𝐹‘𝑋) ≠ 𝑋)) |
| 21 | 12, 20 | mpbird 247 |
. . 3
⊢ ((𝐹:𝐴–1-1-onto→𝐴 ∧ 𝑋 ∈ dom (𝐹 ∖ I )) → (𝐹‘(𝐹‘𝑋)) ≠ (𝐹‘𝑋)) |
| 22 | | fnelnfp 6443 |
. . . 4
⊢ ((𝐹 Fn 𝐴 ∧ (𝐹‘𝑋) ∈ 𝐴) → ((𝐹‘𝑋) ∈ dom (𝐹 ∖ I ) ↔ (𝐹‘(𝐹‘𝑋)) ≠ (𝐹‘𝑋))) |
| 23 | 3, 17, 22 | syl2anc 693 |
. . 3
⊢ ((𝐹:𝐴–1-1-onto→𝐴 ∧ 𝑋 ∈ dom (𝐹 ∖ I )) → ((𝐹‘𝑋) ∈ dom (𝐹 ∖ I ) ↔ (𝐹‘(𝐹‘𝑋)) ≠ (𝐹‘𝑋))) |
| 24 | 21, 23 | mpbird 247 |
. 2
⊢ ((𝐹:𝐴–1-1-onto→𝐴 ∧ 𝑋 ∈ dom (𝐹 ∖ I )) → (𝐹‘𝑋) ∈ dom (𝐹 ∖ I )) |
| 25 | | eldifsn 4317 |
. 2
⊢ ((𝐹‘𝑋) ∈ (dom (𝐹 ∖ I ) ∖ {𝑋}) ↔ ((𝐹‘𝑋) ∈ dom (𝐹 ∖ I ) ∧ (𝐹‘𝑋) ≠ 𝑋)) |
| 26 | 24, 12, 25 | sylanbrc 698 |
1
⊢ ((𝐹:𝐴–1-1-onto→𝐴 ∧ 𝑋 ∈ dom (𝐹 ∖ I )) → (𝐹‘𝑋) ∈ (dom (𝐹 ∖ I ) ∖ {𝑋})) |