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| Mirrors > Home > NFE Home > Th. List > df-disj | GIF version | ||
| Description: Define the relationship of all disjoint sets. (Contributed by SF, 9-Feb-2015.) | 
| Ref | Expression | 
|---|---|
| df-disj | ⊢ Disj = {〈x, y〉 ∣ (x ∩ y) = ∅} | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | cdisj 5744 | . 2 class Disj | |
| 2 | vx | . . . . . 6 setvar x | |
| 3 | 2 | cv 1641 | . . . . 5 class x | 
| 4 | vy | . . . . . 6 setvar y | |
| 5 | 4 | cv 1641 | . . . . 5 class y | 
| 6 | 3, 5 | cin 3209 | . . . 4 class (x ∩ y) | 
| 7 | c0 3551 | . . . 4 class ∅ | |
| 8 | 6, 7 | wceq 1642 | . . 3 wff (x ∩ y) = ∅ | 
| 9 | 8, 2, 4 | copab 4623 | . 2 class {〈x, y〉 ∣ (x ∩ y) = ∅} | 
| 10 | 1, 9 | wceq 1642 | 1 wff Disj = {〈x, y〉 ∣ (x ∩ y) = ∅} | 
| Colors of variables: wff setvar class | 
| This definition is referenced by: brdisjg 5822 disjex 5824 | 
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