Proof of Theorem nomcon1
| Step | Hyp | Ref
| Expression |
| 1 | | ax-a2 31 |
. . . 4
(a ∪ b⊥ ) = (b⊥ ∪ a) |
| 2 | | ax-a1 30 |
. . . . 5
a = a⊥
⊥ |
| 3 | 2 | lor 70 |
. . . 4
(b⊥ ∪ a) = (b⊥ ∪ a⊥ ⊥
) |
| 4 | 1, 3 | ax-r2 36 |
. . 3
(a ∪ b⊥ ) = (b⊥ ∪ a⊥ ⊥
) |
| 5 | | ancom 74 |
. . . . 5
(a ∩ b) = (b ∩
a) |
| 6 | | ax-a1 30 |
. . . . . 6
b = b⊥
⊥ |
| 7 | 6, 2 | 2an 79 |
. . . . 5
(b ∩ a) = (b⊥ ⊥ ∩
a⊥ ⊥
) |
| 8 | 5, 7 | ax-r2 36 |
. . . 4
(a ∩ b) = (b⊥ ⊥ ∩
a⊥ ⊥
) |
| 9 | 8 | lor 70 |
. . 3
(a⊥ ∪ (a ∩ b)) =
(a⊥ ∪ (b⊥ ⊥ ∩
a⊥ ⊥
)) |
| 10 | 4, 9 | 2an 79 |
. 2
((a ∪ b⊥ ) ∩ (a⊥ ∪ (a ∩ b))) =
((b⊥ ∪ a⊥ ⊥ ) ∩
(a⊥ ∪ (b⊥ ⊥ ∩
a⊥ ⊥
))) |
| 11 | | df-id1 50 |
. 2
(a ≡1 b) = ((a ∪
b⊥ ) ∩ (a⊥ ∪ (a ∩ b))) |
| 12 | | df-id2 51 |
. 2
(b⊥ ≡2
a⊥ ) = ((b⊥ ∪ a⊥ ⊥ ) ∩
(a⊥ ∪ (b⊥ ⊥ ∩
a⊥ ⊥
))) |
| 13 | 10, 11, 12 | 3tr1 63 |
1
(a ≡1 b) = (b⊥ ≡2 a⊥ ) |