Proof of Theorem fssxp
| Step | Hyp | Ref
| Expression |
| 1 | | frn 2757 |
. . . 4
⊢ (F:A–→B
→ ran F ⊆ B) |
| 2 | | ssid 1519 |
. . . . 5
⊢ A
⊆ A |
| 3 | | ssxp 2487 |
. . . . 5
⊢ ((A
⊆ A ∧ ran F ⊆ B)
→ (A × ran F) ⊆ (A
× B)) |
| 4 | 2, 3 | mpan 518 |
. . . 4
⊢ (ran F
⊆ B → (A × ran F)
⊆ (A × B)) |
| 5 | 1, 4 | syl 12 |
. . 3
⊢ (F:A–→B
→ (A × ran F) ⊆ (A
× B)) |
| 6 | | fdm 2756 |
. . . 4
⊢ (F:A–→B
→ dom F = A) |
| 7 | | xpeq1 2440 |
. . . 4
⊢ (dom F
= A → (dom F × ran F)
= (A × ran F)) |
| 8 | | sseq1 1521 |
. . . 4
⊢ ((dom F × ran F)
= (A × ran F) → ((dom F × ran F)
⊆ (A × B) ↔ (A
× ran F) ⊆ (A × B))) |
| 9 | 6, 7, 8 | 3syl 21 |
. . 3
⊢ (F:A–→B
→ ((dom F × ran F) ⊆ (A
× B) ↔ (A × ran F)
⊆ (A × B))) |
| 10 | 5, 9 | mpbird 171 |
. 2
⊢ (F:A–→B
→ (dom F × ran F) ⊆ (A
× B)) |
| 11 | | frel 2755 |
. . 3
⊢ (F:A–→B
→ Rel F) |
| 12 | | relssdr 2668 |
. . 3
⊢ (Rel F
→ F ⊆ (dom F × ran F)) |
| 13 | | sstr2 1510 |
. . 3
⊢ (F
⊆ (dom F × ran F) → ((dom F × ran F)
⊆ (A × B) → F
⊆ (A × B))) |
| 14 | 11, 12, 13 | 3syl 21 |
. 2
⊢ (F:A–→B
→ ((dom F × ran F) ⊆ (A
× B) → F ⊆ (A
× B))) |
| 15 | 10, 14 | mpd 46 |
1
⊢ (F:A–→B
→ F ⊆ (A × B)) |