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| Description: Define unordered triple of classes. Definition of [Enderton] p. 19. |
| Ref | Expression |
|---|---|
| df-tp |
|
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | cA |
. . 3
| |
| 2 | cB |
. . 3
| |
| 3 | cC |
. . 3
| |
| 4 | 1, 2, 3 | ctp 2412 |
. 2
|
| 5 | 1, 2 | cpr 2408 |
. . 3
|
| 6 | 3 | csn 2407 |
. . 3
|
| 7 | 5, 6 | cun 2043 |
. 2
|
| 8 | 4, 7 | wceq 956 |
1
|
| Colors of variables: wff set class |
| This definition is referenced by: eltp 2437 tpi1 2453 tpi2 2454 tpi3 2455 tpex 2876 |