Proof of Theorem ud5lem0b
| Step | Hyp | Ref
| Expression |
| 1 | | ud5lem0a.1 |
. . . . 5
a = b |
| 2 | 1 | ran 71 |
. . . 4
(a ∩ c) = (b ∩
c) |
| 3 | 1 | ax-r4 36 |
. . . . 5
a⊥ = b⊥ |
| 4 | 3 | ran 71 |
. . . 4
(a⊥ ∩ c) = (b⊥ ∩ c) |
| 5 | 2, 4 | 2or 67 |
. . 3
((a ∩ c) ∪ (a⊥ ∩ c)) = ((b ∩
c) ∪ (b⊥ ∩ c)) |
| 6 | 3 | ran 71 |
. . 3
(a⊥ ∩ c⊥ ) = (b⊥ ∩ c⊥ ) |
| 7 | 5, 6 | 2or 67 |
. 2
(((a ∩ c) ∪ (a⊥ ∩ c)) ∪ (a⊥ ∩ c⊥ )) = (((b ∩ c) ∪
(b⊥ ∩ c)) ∪ (b⊥ ∩ c⊥ )) |
| 8 | | df-i5 47 |
. 2
(a →5 c) = (((a ∩
c) ∪ (a⊥ ∩ c)) ∪ (a⊥ ∩ c⊥ )) |
| 9 | | df-i5 47 |
. 2
(b →5 c) = (((b ∩
c) ∪ (b⊥ ∩ c)) ∪ (b⊥ ∩ c⊥ )) |
| 10 | 7, 8, 9 | 3tr1 60 |
1
(a →5 c) = (b
→5 c) |