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| Description: Define the union of a class i.e. the collection of all members of the members of the class. Definition 5.5 of [TakeutiZaring] p. 16. |
| Ref | Expression |
|---|---|
| df-uni |
|
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | cA |
. . 3
| |
| 2 | 1 | cuni 2493 |
. 2
|
| 3 | vx |
. . . . . . 7
| |
| 4 | 3 | cv 952 |
. . . . . 6
|
| 5 | vy |
. . . . . . 7
| |
| 6 | 5 | cv 952 |
. . . . . 6
|
| 7 | 4, 6 | wcel 955 |
. . . . 5
|
| 8 | 6, 1 | wcel 955 |
. . . . 5
|
| 9 | 7, 8 | wa 223 |
. . . 4
|
| 10 | 9, 5 | wex 977 |
. . 3
|
| 11 | 10, 3 | cab 1456 |
. 2
|
| 12 | 2, 11 | wceq 953 |
1
|
| Colors of variables: wff set class |
| This definition is referenced by: dfuni2 2495 eluni 2496 unieq 2500 unipr 2505 uniss 2511 dfiun2g 2576 uniuni 2870 |