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Related theorems GIF version |
| Description: Define the cross product of two classes. Definition 9.11 of [Quine] p. 64. |
| Ref | Expression |
|---|---|
| df-xp | ⊢ (A × B) = {〈x, y〉∣(x ∈ A ∧ y ∈ B)} |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | cA | . . 3 class A | |
| 2 | cB | . . 3 class B | |
| 3 | 1, 2 | cxp 2408 | . 2 class (A × B) |
| 4 | vx | . . . . . 6 set x | |
| 5 | 4 | cv 1089 | . . . . 5 class x |
| 6 | 5, 1 | wcel 1092 | . . . 4 wff x ∈ A |
| 7 | vy | . . . . . 6 set y | |
| 8 | 7 | cv 1089 | . . . . 5 class y |
| 9 | 8, 2 | wcel 1092 | . . . 4 wff y ∈ B |
| 10 | 6, 9 | wa 196 | . . 3 wff (x ∈ A ∧ y ∈ B) |
| 11 | 10, 4, 7 | copab 2055 | . 2 class {〈x, y〉∣(x ∈ A ∧ y ∈ B)} |
| 12 | 3, 11 | wceq 1091 | 1 wff (A × B) = {〈x, y〉∣(x ∈ A ∧ y ∈ B)} |
| Colors of variables: wff set class |
| This definition is referenced by: xpeq1 2440 xpeq2 2441 elxp 2442 fconstopab 2448 xpundi 2461 xpundir 2462 opabssxp 2468 relopab 2494 dmxp 2552 resopab 2598 fnoprab2 3039 1st2val 3097 aceq3 3556 genpdm 3899 infmap2lem2 4952 |