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Mirrors > Home > NFE Home > Th. List > df-xp | GIF version |
Description: Define the cross product of two classes. Definition 9.11 of [Quine] p. 64. (Contributed by SF, 5-Jan-2015.) |
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 4771 | . 2 class (A × B) |
4 | vx | . . . . . 6 setvar x | |
5 | 4 | cv 1641 | . . . . 5 class x |
6 | 5, 1 | wcel 1710 | . . . 4 wff x ∈ A |
7 | vy | . . . . . 6 setvar y | |
8 | 7 | cv 1641 | . . . . 5 class y |
9 | 8, 2 | wcel 1710 | . . . 4 wff y ∈ B |
10 | 6, 9 | wa 358 | . . 3 wff (x ∈ A ∧ y ∈ B) |
11 | 10, 4, 7 | copab 4623 | . 2 class {〈x, y〉 ∣ (x ∈ A ∧ y ∈ B)} |
12 | 3, 11 | wceq 1642 | 1 wff (A × B) = {〈x, y〉 ∣ (x ∈ A ∧ y ∈ B)} |
Colors of variables: wff setvar class |
This definition is referenced by: xpeq1 4799 xpeq2 4800 elxpi 4801 elxp 4802 nfxp 4811 csbxpg 4814 fconstopab 4816 xpundi 4833 xpundir 4834 opabssxp 4838 xpss12 4856 inxp 4864 dmxp 4924 resopab 5000 cnvxp 5044 ovg 5602 composefn 5819 fnce 6177 |
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