Step |
Hyp |
Ref |
Expression |
1 |
|
tposfo2 |
⊢ ( Rel 𝐴 → ( 𝐹 : 𝐴 –onto→ ran 𝐹 → tpos 𝐹 : ◡ 𝐴 –onto→ ran 𝐹 ) ) |
2 |
|
ffn |
⊢ ( 𝐹 : 𝐴 ⟶ 𝐵 → 𝐹 Fn 𝐴 ) |
3 |
|
dffn4 |
⊢ ( 𝐹 Fn 𝐴 ↔ 𝐹 : 𝐴 –onto→ ran 𝐹 ) |
4 |
2 3
|
sylib |
⊢ ( 𝐹 : 𝐴 ⟶ 𝐵 → 𝐹 : 𝐴 –onto→ ran 𝐹 ) |
5 |
1 4
|
impel |
⊢ ( ( Rel 𝐴 ∧ 𝐹 : 𝐴 ⟶ 𝐵 ) → tpos 𝐹 : ◡ 𝐴 –onto→ ran 𝐹 ) |
6 |
|
fof |
⊢ ( tpos 𝐹 : ◡ 𝐴 –onto→ ran 𝐹 → tpos 𝐹 : ◡ 𝐴 ⟶ ran 𝐹 ) |
7 |
5 6
|
syl |
⊢ ( ( Rel 𝐴 ∧ 𝐹 : 𝐴 ⟶ 𝐵 ) → tpos 𝐹 : ◡ 𝐴 ⟶ ran 𝐹 ) |
8 |
|
frn |
⊢ ( 𝐹 : 𝐴 ⟶ 𝐵 → ran 𝐹 ⊆ 𝐵 ) |
9 |
8
|
adantl |
⊢ ( ( Rel 𝐴 ∧ 𝐹 : 𝐴 ⟶ 𝐵 ) → ran 𝐹 ⊆ 𝐵 ) |
10 |
7 9
|
fssd |
⊢ ( ( Rel 𝐴 ∧ 𝐹 : 𝐴 ⟶ 𝐵 ) → tpos 𝐹 : ◡ 𝐴 ⟶ 𝐵 ) |
11 |
10
|
ex |
⊢ ( Rel 𝐴 → ( 𝐹 : 𝐴 ⟶ 𝐵 → tpos 𝐹 : ◡ 𝐴 ⟶ 𝐵 ) ) |