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Mirrors > Home > NFE Home > Th. List > df-id | Unicode version |
Description: Define the identity relation. Definition 9.15 of [Quine] p. 64. (Contributed by SF, 5-Jan-2015.) |
Ref | Expression |
---|---|
df-id |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | cid 4763 | . 2 | |
2 | vx | . . . 4 | |
3 | vy | . . . 4 | |
4 | 2, 3 | weq 1643 | . . 3 |
5 | 4, 2, 3 | copab 4622 | . 2 |
6 | 1, 5 | wceq 1642 | 1 |
Colors of variables: wff setvar class |
This definition is referenced by: dfid3 4768 ideqg 4868 ideqg2 4869 cnvi 5032 |
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