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| Description: Define the cross product of two classes. Definition 9.11 of [Quine] p. 64. |
| Ref | Expression |
|---|---|
| df-xp |
|
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | cA |
. . 3
| |
| 2 | cB |
. . 3
| |
| 3 | 1, 2 | cxp 3164 |
. 2
|
| 4 | vx |
. . . . . 6
| |
| 5 | 4 | cv 954 |
. . . . 5
|
| 6 | 5, 1 | wcel 957 |
. . . 4
|
| 7 | vy |
. . . . . 6
| |
| 8 | 7 | cv 954 |
. . . . 5
|
| 9 | 8, 2 | wcel 957 |
. . . 4
|
| 10 | 6, 9 | wa 223 |
. . 3
|
| 11 | 10, 4, 7 | copab 2662 |
. 2
|
| 12 | 3, 11 | wceq 955 |
1
|
| Colors of variables: wff set class |
| This definition is referenced by: xpeq1 3196 xpeq2 3197 elxp 3198 fconstopab 3206 xpundi 3221 xpundir 3222 opabssxp 3230 relopab 3262 dmxp 3328 resopab 3391 1st2val 4088 2nd2val 4089 aceq3 4716 genpdm 5088 infmap2lem2 7540 ajfval 8428 |