Proof of Theorem cdaassen
| Step | Hyp | Ref
| Expression |
| 1 | | cdacomen.1 |
. . . . . . . . 9
⊢ A
∈ V |
| 2 | | p0ex 1885 |
. . . . . . . . 9
⊢ {∅} ∈ V |
| 3 | 1, 2 | xpex 2488 |
. . . . . . . 8
⊢ (A
× {∅}) ∈ V |
| 4 | | cdacomen.2 |
. . . . . . . . 9
⊢ B
∈ V |
| 5 | | snex 1859 |
. . . . . . . . 9
⊢ {1o} ∈
V |
| 6 | 4, 5 | xpex 2488 |
. . . . . . . 8
⊢ (B
× {1o}) ∈ V |
| 7 | 3, 6 | unex 1949 |
. . . . . . 7
⊢ ((A
× {∅}) ∪ (B ×
{1o})) ∈ V |
| 8 | 7, 2 | xpex 2488 |
. . . . . 6
⊢ (((A
× {∅}) ∪ (B ×
{1o})) × {∅}) ∈ V |
| 9 | | xpundir 2462 |
. . . . . 6
⊢ (((A
× {∅}) ∪ (B ×
{1o})) × {∅}) = (((A × {∅}) × {∅}) ∪
((B × {1o}) ×
{∅})) |
| 10 | | eqeng 3296 |
. . . . . 6
⊢ ((((A
× {∅}) ∪ (B ×
{1o})) × {∅}) ∈ V → ((((A × {∅}) ∪ (B × {1o})) ×
{∅}) = (((A × {∅})
× {∅}) ∪ ((B ×
{1o}) × {∅})) → (((A × {∅}) ∪ (B × {1o})) ×
{∅}) ≈ (((A × {∅})
× {∅}) ∪ ((B ×
{1o}) × {∅})))) |
| 11 | 8, 9, 10 | mp2 43 |
. . . . 5
⊢ (((A
× {∅}) ∪ (B ×
{1o})) × {∅}) ≈ (((A × {∅}) × {∅}) ∪
((B × {1o}) ×
{∅})) |
| 12 | | cdaassen.3 |
. . . . . . 7
⊢ C
∈ V |
| 13 | 12, 5 | xpex 2488 |
. . . . . 6
⊢ (C
× {1o}) ∈ V |
| 14 | | 1o 3109 |
. . . . . . . 8
⊢ 1o ∈ On |
| 15 | 14 | elisseti 1355 |
. . . . . . 7
⊢ 1o ∈
V |
| 16 | 13, 15 | xpsnen 3339 |
. . . . . 6
⊢ ((C
× {1o}) × {1o}) ≈
(C ×
{1o}) |
| 17 | 13, 16 | ensymi 3318 |
. . . . 5
⊢ (C
× {1o}) ≈ ((C
× {1o}) × {1o}) |
| 18 | 11, 17 | pm3.2i 234 |
. . . 4
⊢ ((((A
× {∅}) ∪ (B ×
{1o})) × {∅}) ≈ (((A × {∅}) × {∅}) ∪
((B × {1o}) ×
{∅})) ∧ (C ×
{1o}) ≈ ((C ×
{1o}) × {1o})) |
| 19 | | 0ne1oOLD 3113 |
. . . . . 6
⊢ ¬ ∅ =
1o |
| 20 | | xpsndisj 2655 |
. . . . . 6
⊢ (¬ ∅ = 1o
→ ((((A × {∅}) ∪
(B × {1o})) ×
{∅}) ∩ (C ×
{1o})) = ∅) |
| 21 | 19, 20 | ax-mp 6 |
. . . . 5
⊢ ((((A
× {∅}) ∪ (B ×
{1o})) × {∅}) ∩ (C × {1o})) =
∅ |
| 22 | | xpsndisj 2655 |
. . . . . . . 8
⊢ (¬ ∅ = 1o
→ (((A × {∅}) ×
{∅}) ∩ ((C ×
{1o}) × {1o})) = ∅) |
| 23 | 19, 22 | ax-mp 6 |
. . . . . . 7
⊢ (((A
× {∅}) × {∅}) ∩ ((C × {1o}) ×
{1o})) = ∅ |
| 24 | | xpsndisj 2655 |
. . . . . . . 8
⊢ (¬ ∅ = 1o
→ (((B × {1o})
× {∅}) ∩ ((C ×
{1o}) × {1o})) = ∅) |
| 25 | 19, 24 | ax-mp 6 |
. . . . . . 7
⊢ (((B
× {1o}) × {∅}) ∩ ((C × {1o}) ×
{1o})) = ∅ |
| 26 | 23, 25 | pm3.2i 234 |
. . . . . 6
⊢ ((((A
× {∅}) × {∅}) ∩ ((C × {1o}) ×
{1o})) = ∅ ∧ (((B × {1o}) × {∅})
∩ ((C × {1o})
× {1o})) = ∅) |
| 27 | | undisj1 1739 |
. . . . . 6
⊢ (((((A
× {∅}) × {∅}) ∩ ((C × {1o}) ×
{1o})) = ∅ ∧ (((B × {1o}) × {∅})
∩ ((C × {1o})
× {1o})) = ∅) ↔ ((((A × {∅}) × {∅}) ∪
((B × {1o}) ×
{∅})) ∩ ((C ×
{1o}) × {1o})) = ∅) |
| 28 | 26, 27 | mpbi 164 |
. . . . 5
⊢ ((((A
× {∅}) × {∅}) ∪ ((B × {1o}) ×
{∅})) ∩ ((C ×
{1o}) × {1o})) = ∅ |
| 29 | 21, 28 | pm3.2i 234 |
. . . 4
⊢ (((((A
× {∅}) ∪ (B ×
{1o})) × {∅}) ∩ (C × {1o})) = ∅ ∧
((((A × {∅}) × {∅})
∪ ((B × {1o})
× {∅})) ∩ ((C ×
{1o}) × {1o})) = ∅) |
| 30 | | unen 3338 |
. . . 4
⊢ ((((((A × {∅}) ∪ (B × {1o})) ×
{∅}) ≈ (((A × {∅})
× {∅}) ∪ ((B ×
{1o}) × {∅})) ∧ (C × {1o}) ≈ ((C × {1o}) ×
{1o})) ∧ (((((A
× {∅}) ∪ (B ×
{1o})) × {∅}) ∩ (C × {1o})) = ∅ ∧
((((A × {∅}) × {∅})
∪ ((B × {1o})
× {∅})) ∩ ((C ×
{1o}) × {1o})) = ∅)) →
((((A × {∅}) ∪ (B × {1o})) ×
{∅}) ∪ (C ×
{1o})) ≈ ((((A
× {∅}) × {∅}) ∪ ((B × {1o}) ×
{∅})) ∪ ((C ×
{1o}) × {1o}))) |
| 31 | 18, 29, 30 | mp2an 520 |
. . 3
⊢ ((((A
× {∅}) ∪ (B ×
{1o})) × {∅}) ∪ (C × {1o})) ≈
((((A × {∅}) × {∅})
∪ ((B × {1o})
× {∅})) ∪ ((C ×
{1o}) × {1o})) |
| 32 | 3, 2 | xpex 2488 |
. . . . 5
⊢ ((A
× {∅}) × {∅}) ∈ V |
| 33 | 4, 2 | xpex 2488 |
. . . . . . 7
⊢ (B
× {∅}) ∈ V |
| 34 | 33, 5 | xpex 2488 |
. . . . . 6
⊢ ((B
× {∅}) × {1o}) ∈ V |
| 35 | 13, 5 | xpex 2488 |
. . . . . 6
⊢ ((C
× {1o}) × {1o}) ∈
V |
| 36 | 34, 35 | unex 1949 |
. . . . 5
⊢ (((B
× {∅}) × {1o}) ∪ ((C × {1o}) ×
{1o})) ∈ V |
| 37 | 32, 36 | unex 1949 |
. . . 4
⊢ (((A
× {∅}) × {∅}) ∪ (((B × {∅}) × {1o})
∪ ((C × {1o})
× {1o}))) ∈ V |
| 38 | 32 | enref 3295 |
. . . . . . . . 9
⊢ ((A
× {∅}) × {∅}) ≈ ((A × {∅}) × {∅}) |
| 39 | 4, 5, 2 | xpassen 3344 |
. . . . . . . . . 10
⊢ ((B
× {1o}) × {∅}) ≈ (B × ({1o} ×
{∅})) |
| 40 | 2, 5 | xpex 2488 |
. . . . . . . . . . . 12
⊢ ({∅} × {1o})
∈ V |
| 41 | 4, 40 | xpex 2488 |
. . . . . . . . . . 11
⊢ (B
× ({∅} × {1o})) ∈ V |
| 42 | 4 | enref 3295 |
. . . . . . . . . . . 12
⊢ B
≈ B |
| 43 | 5, 2 | xpcomen 3343 |
. . . . . . . . . . . 12
⊢ ({1o} × {∅})
≈ ({∅} × {1o}) |
| 44 | 5, 2 | xpex 2488 |
. . . . . . . . . . . . 13
⊢ ({1o} × {∅})
∈ V |
| 45 | 4, 4, 44, 40 | xpen 3383 |
. . . . . . . . . . . 12
⊢ ((B
≈ B ∧ ({1o}
× {∅}) ≈ ({∅} × {1o})) →
(B × ({1o} ×
{∅})) ≈ (B × ({∅}
× {1o}))) |
| 46 | 42, 43, 45 | mp2an 520 |
. . . . . . . . . . 11
⊢ (B
× ({1o} × {∅})) ≈ (B × ({∅} ×
{1o})) |
| 47 | 4, 2, 5 | xpassen 3344 |
. . . . . . . . . . 11
⊢ ((B
× {∅}) × {1o}) ≈ (B × ({∅} ×
{1o})) |
| 48 | 41, 46, 47 | entr4 3324 |
. . . . . . . . . 10
⊢ (B
× ({1o} × {∅})) ≈ ((B × {∅}) ×
{1o}) |
| 49 | 39, 48 | entr 3321 |
. . . . . . . . 9
⊢ ((B
× {1o}) × {∅}) ≈ ((B × {∅}) ×
{1o}) |
| 50 | 38, 49 | pm3.2i 234 |
. . . . . . . 8
⊢ (((A
× {∅}) × {∅}) ≈ ((A × {∅}) × {∅}) ∧
((B × {1o}) ×
{∅}) ≈ ((B × {∅})
× {1o})) |
| 51 | | xpsndisj 2655 |
. . . . . . . . . . . 12
⊢ (¬ ∅ = 1o
→ ((A × {∅}) ∩
(B × {1o})) =
∅) |
| 52 | 19, 51 | ax-mp 6 |
. . . . . . . . . . 11
⊢ ((A
× {∅}) ∩ (B ×
{1o})) = ∅ |
| 53 | | xpeq1 2440 |
. . . . . . . . . . 11
⊢ (((A
× {∅}) ∩ (B ×
{1o})) = ∅ → (((A × {∅}) ∩ (B × {1o})) ×
{∅}) = (∅ × {∅})) |
| 54 | 52, 53 | ax-mp 6 |
. . . . . . . . . 10
⊢ (((A
× {∅}) ∩ (B ×
{1o})) × {∅}) = (∅ ×
{∅}) |
| 55 | | xpindir 2498 |
. . . . . . . . . 10
⊢ (((A
× {∅}) ∩ (B ×
{1o})) × {∅}) = (((A × {∅}) × {∅}) ∩
((B × {1o}) ×
{∅})) |
| 56 | | xp0r 2474 |
. . . . . . . . . 10
⊢ (∅ × {∅}) =
∅ |
| 57 | 54, 55, 56 | 3eqtr3 1124 |
. . . . . . . . 9
⊢ (((A
× {∅}) × {∅}) ∩ ((B × {1o}) ×
{∅})) = ∅ |
| 58 | | xpsndisj 2655 |
. . . . . . . . . 10
⊢ (¬ ∅ = 1o
→ (((A × {∅}) ×
{∅}) ∩ ((B × {∅})
× {1o})) = ∅) |
| 59 | 19, 58 | ax-mp 6 |
. . . . . . . . 9
⊢ (((A
× {∅}) × {∅}) ∩ ((B × {∅}) ×
{1o})) = ∅ |
| 60 | 57, 59 | pm3.2i 234 |
. . . . . . . 8
⊢ ((((A
× {∅}) × {∅}) ∩ ((B × {1o}) ×
{∅})) = ∅ ∧ (((A ×
{∅}) × {∅}) ∩ ((B
× {∅}) × {1o})) = ∅) |
| 61 | | unen 3338 |
. . . . . . . 8
⊢ (((((A
× {∅}) × {∅}) ≈ ((A × {∅}) × {∅}) ∧
((B × {1o}) ×
{∅}) ≈ ((B × {∅})
× {1o})) ∧ ((((A × {∅}) × {∅}) ∩
((B × {1o}) ×
{∅})) = ∅ ∧ (((A ×
{∅}) × {∅}) ∩ ((B
× {∅}) × {1o})) = ∅)) →
(((A × {∅}) × {∅})
∪ ((B × {1o})
× {∅})) ≈ (((A ×
{∅}) × {∅}) ∪ ((B
× {∅}) × {1o}))) |
| 62 | 50, 60, 61 | mp2an 520 |
. . . . . . 7
⊢ (((A
× {∅}) × {∅}) ∪ ((B × {1o}) ×
{∅})) ≈ (((A × {∅})
× {∅}) ∪ ((B ×
{∅}) × {1o})) |
| 63 | 35 | enref 3295 |
. . . . . . 7
⊢ ((C
× {1o}) × {1o}) ≈
((C × {1o}) ×
{1o}) |
| 64 | 62, 63 | pm3.2i 234 |
. . . . . 6
⊢ ((((A
× {∅}) × {∅}) ∪ ((B × {1o}) ×
{∅})) ≈ (((A × {∅})
× {∅}) ∪ ((B ×
{∅}) × {1o})) ∧ ((C × {1o}) ×
{1o}) ≈ ((C ×
{1o}) × {1o})) |
| 65 | | xpsndisj 2655 |
. . . . . . . . . . . 12
⊢ (¬ ∅ = 1o
→ ((B × {∅}) ∩
(C × {1o})) =
∅) |
| 66 | 19, 65 | ax-mp 6 |
. . . . . . . . . . 11
⊢ ((B
× {∅}) ∩ (C ×
{1o})) = ∅ |
| 67 | | xpeq1 2440 |
. . . . . . . . . . 11
⊢ (((B
× {∅}) ∩ (C ×
{1o})) = ∅ → (((B × {∅}) ∩ (C × {1o})) ×
{1o}) = (∅ × {1o})) |
| 68 | 66, 67 | ax-mp 6 |
. . . . . . . . . 10
⊢ (((B
× {∅}) ∩ (C ×
{1o})) × {1o}) = (∅ ×
{1o}) |
| 69 | | xpindir 2498 |
. . . . . . . . . 10
⊢ (((B
× {∅}) ∩ (C ×
{1o})) × {1o}) = (((B × {∅}) × {1o})
∩ ((C × {1o})
× {1o})) |
| 70 | | xp0r 2474 |
. . . . . . . . . 10
⊢ (∅ × {1o}) =
∅ |
| 71 | 68, 69, 70 | 3eqtr3 1124 |
. . . . . . . . 9
⊢ (((B
× {∅}) × {1o}) ∩ ((C × {1o}) ×
{1o})) = ∅ |
| 72 | 23, 71 | pm3.2i 234 |
. . . . . . . 8
⊢ ((((A
× {∅}) × {∅}) ∩ ((C × {1o}) ×
{1o})) = ∅ ∧ (((B × {∅}) × {1o})
∩ ((C × {1o})
× {1o})) = ∅) |
| 73 | | undisj1 1739 |
. . . . . . . 8
⊢ (((((A
× {∅}) × {∅}) ∩ ((C × {1o}) ×
{1o})) = ∅ ∧ (((B × {∅}) × {1o})
∩ ((C × {1o})
× {1o})) = ∅) ↔ ((((A × {∅}) × {∅}) ∪
((B × {∅}) ×
{1o})) ∩ ((C ×
{1o}) × {1o})) = ∅) |
| 74 | 72, 73 | mpbi 164 |
. . . . . . 7
⊢ ((((A
× {∅}) × {∅}) ∪ ((B × {∅}) ×
{1o})) ∩ ((C ×
{1o}) × {1o})) = ∅ |
| 75 | 28, 74 | pm3.2i 234 |
. . . . . 6
⊢ (((((A
× {∅}) × {∅}) ∪ ((B × {1o}) ×
{∅})) ∩ ((C ×
{1o}) × {1o})) = ∅ ∧
((((A × {∅}) × {∅})
∪ ((B × {∅}) ×
{1o})) ∩ ((C ×
{1o}) × {1o})) = ∅) |
| 76 | | unen 3338 |
. . . . . 6
⊢ ((((((A × {∅}) × {∅}) ∪
((B × {1o}) ×
{∅})) ≈ (((A × {∅})
× {∅}) ∪ ((B ×
{∅}) × {1o})) ∧ ((C × {1o}) ×
{1o}) ≈ ((C ×
{1o}) × {1o})) ∧ (((((A × {∅}) × {∅}) ∪
((B × {1o}) ×
{∅})) ∩ ((C ×
{1o}) × {1o})) = ∅ ∧
((((A × {∅}) × {∅})
∪ ((B × {∅}) ×
{1o})) ∩ ((C ×
{1o}) × {1o})) = ∅)) →
((((A × {∅}) × {∅})
∪ ((B × {1o})
× {∅})) ∪ ((C ×
{1o}) × {1o})) ≈ ((((A × {∅}) × {∅}) ∪
((B × {∅}) ×
{1o})) ∪ ((C ×
{1o}) × {1o}))) |
| 77 | 64, 75, 76 | mp2an 520 |
. . . . 5
⊢ ((((A
× {∅}) × {∅}) ∪ ((B × {1o}) ×
{∅})) ∪ ((C ×
{1o}) × {1o})) ≈ ((((A × {∅}) × {∅}) ∪
((B × {∅}) ×
{1o})) ∪ ((C ×
{1o}) × {1o})) |
| 78 | | unass 1615 |
. . . . 5
⊢ ((((A
× {∅}) × {∅}) ∪ ((B × {∅}) ×
{1o})) ∪ ((C ×
{1o}) × {1o})) = (((A × {∅}) × {∅}) ∪
(((B × {∅}) ×
{1o}) ∪ ((C ×
{1o}) × {1o}))) |
| 79 | 77, 78 | breqtr 2080 |
. . . 4
⊢ ((((A
× {∅}) × {∅}) ∪ ((B × {1o}) ×
{∅})) ∪ ((C ×
{1o}) × {1o})) ≈ (((A × {∅}) × {∅}) ∪
(((B × {∅}) ×
{1o}) ∪ ((C ×
{1o}) × {1o}))) |
| 80 | | 0ex 1745 |
. . . . . . . 8
⊢ ∅ ∈ V |
| 81 | 3, 80 | xpsnen 3339 |
. . . . . . 7
⊢ ((A
× {∅}) × {∅}) ≈ (A × {∅}) |
| 82 | 3, 81 | ensymi 3318 |
. . . . . 6
⊢ (A
× {∅}) ≈ ((A ×
{∅}) × {∅}) |
| 83 | 33, 13 | unex 1949 |
. . . . . . . 8
⊢ ((B
× {∅}) ∪ (C ×
{1o})) ∈ V |
| 84 | 83, 5 | xpex 2488 |
. . . . . . 7
⊢ (((B
× {∅}) ∪ (C ×
{1o})) × {1o}) ∈
V |
| 85 | | xpundir 2462 |
. . . . . . 7
⊢ (((B
× {∅}) ∪ (C ×
{1o})) × {1o}) = (((B × {∅}) × {1o})
∪ ((C × {1o})
× {1o})) |
| 86 | | eqeng 3296 |
. . . . . . 7
⊢ ((((B
× {∅}) ∪ (C ×
{1o})) × {1o}) ∈ V →
((((B × {∅}) ∪ (C × {1o})) ×
{1o}) = (((B ×
{∅}) × {1o}) ∪ ((C × {1o}) ×
{1o})) → (((B
× {∅}) ∪ (C ×
{1o})) × {1o}) ≈ (((B × {∅}) × {1o})
∪ ((C × {1o})
× {1o})))) |
| 87 | 84, 85, 86 | mp2 43 |
. . . . . 6
⊢ (((B
× {∅}) ∪ (C ×
{1o})) × {1o}) ≈ (((B × {∅}) × {1o})
∪ ((C × {1o})
× {1o})) |
| 88 | 82, 87 | pm3.2i 234 |
. . . . 5
⊢ ((A
× {∅}) ≈ ((A ×
{∅}) × {∅}) ∧ (((B
× {∅}) ∪ (C ×
{1o})) × {1o}) ≈ (((B × {∅}) × {1o})
∪ ((C × {1o})
× {1o}))) |
| 89 | | xpsndisj 2655 |
. . . . . . 7
⊢ (¬ ∅ = 1o
→ ((A × {∅}) ∩
(((B × {∅}) ∪ (C × {1o})) ×
{1o})) = ∅) |
| 90 | 19, 89 | ax-mp 6 |
. . . . . 6
⊢ ((A
× {∅}) ∩ (((B ×
{∅}) ∪ (C ×
{1o})) × {1o})) = ∅ |
| 91 | 59, 23 | pm3.2i 234 |
. . . . . . 7
⊢ ((((A
× {∅}) × {∅}) ∩ ((B × {∅}) ×
{1o})) = ∅ ∧ (((A × {∅}) × {∅}) ∩
((C × {1o}) ×
{1o})) = ∅) |
| 92 | | undisj2 1740 |
. . . . . . 7
⊢ (((((A
× {∅}) × {∅}) ∩ ((B × {∅}) ×
{1o})) = ∅ ∧ (((A × {∅}) × {∅}) ∩
((C × {1o}) ×
{1o})) = ∅) ↔ (((A × {∅}) × {∅}) ∩
(((B × {∅}) ×
{1o}) ∪ ((C ×
{1o}) × {1o}))) = ∅) |
| 93 | 91, 92 | mpbi 164 |
. . . . . 6
⊢ (((A
× {∅}) × {∅}) ∩ (((B × {∅}) × {1o})
∪ ((C × {1o})
× {1o}))) = ∅ |
| 94 | 90, 93 | pm3.2i 234 |
. . . . 5
⊢ (((A
× {∅}) ∩ (((B ×
{∅}) ∪ (C ×
{1o})) × {1o})) = ∅ ∧
(((A × {∅}) × {∅})
∩ (((B × {∅}) ×
{1o}) ∪ ((C ×
{1o}) × {1o}))) = ∅) |
| 95 | | unen 3338 |
. . . . 5
⊢ ((((A
× {∅}) ≈ ((A ×
{∅}) × {∅}) ∧ (((B
× {∅}) ∪ (C ×
{1o})) × {1o}) ≈ (((B × {∅}) × {1o})
∪ ((C × {1o})
× {1o}))) ∧ (((A × {∅}) ∩ (((B × {∅}) ∪ (C × {1o})) ×
{1o})) = ∅ ∧ (((A × {∅}) × {∅}) ∩
(((B × {∅}) ×
{1o}) ∪ ((C ×
{1o}) × {1o}))) = ∅)) →
((A × {∅}) ∪ (((B × {∅}) ∪ (C × {1o})) ×
{1o})) ≈ (((A
× {∅}) × {∅}) ∪ (((B × {∅}) × {1o})
∪ ((C × {1o})
× {1o})))) |
| 96 | 88, 94, 95 | mp2an 520 |
. . . 4
⊢ ((A
× {∅}) ∪ (((B ×
{∅}) ∪ (C ×
{1o})) × {1o})) ≈ (((A × {∅}) × {∅}) ∪
(((B × {∅}) ×
{1o}) ∪ ((C ×
{1o}) × {1o}))) |
| 97 | 37, 79, 96 | entr4 3324 |
. . 3
⊢ ((((A
× {∅}) × {∅}) ∪ ((B × {1o}) ×
{∅})) ∪ ((C ×
{1o}) × {1o})) ≈ ((A × {∅}) ∪ (((B × {∅}) ∪ (C × {1o})) ×
{1o})) |
| 98 | 31, 97 | entr 3321 |
. 2
⊢ ((((A
× {∅}) ∪ (B ×
{1o})) × {∅}) ∪ (C × {1o})) ≈
((A × {∅}) ∪ (((B × {∅}) ∪ (C × {1o})) ×
{1o})) |
| 99 | 1, 4 | cdaval 3717 |
. . . 4
⊢ (A
+c B) = ((A × {∅}) ∪ (B × {1o})) |
| 100 | 99 | opreq1i 3009 |
. . 3
⊢ ((A
+c B)
+c C) = (((A × {∅}) ∪ (B × {1o}))
+c C) |
| 101 | 7, 12 | cdaval 3717 |
. . 3
⊢ (((A
× {∅}) ∪ (B ×
{1o})) +c C) = ((((A
× {∅}) ∪ (B ×
{1o})) × {∅}) ∪ (C × {1o})) |
| 102 | 100, 101 | eqtr 1119 |
. 2
⊢ ((A
+c B)
+c C) = ((((A × {∅}) ∪ (B × {1o})) ×
{∅}) ∪ (C ×
{1o})) |
| 103 | 4, 12 | cdaval 3717 |
. . . 4
⊢ (B
+c C) = ((B × {∅}) ∪ (C × {1o})) |
| 104 | 103 | opreq2i 3010 |
. . 3
⊢ (A
+c (B
+c C)) = (A +c ((B × {∅}) ∪ (C × {1o}))) |
| 105 | 1, 83 | cdaval 3717 |
. . 3
⊢ (A
+c ((B × {∅})
∪ (C × {1o})))
= ((A × {∅}) ∪ (((B × {∅}) ∪ (C × {1o})) ×
{1o})) |
| 106 | 104, 105 | eqtr 1119 |
. 2
⊢ (A
+c (B
+c C)) = ((A × {∅}) ∪ (((B × {∅}) ∪ (C × {1o})) ×
{1o})) |
| 107 | 98, 102, 106 | 3brtr4 2085 |
1
⊢ ((A
+c B)
+c C) ≈ (A +c (B +c C)) |