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| Mirrors > Home > NFE Home > Th. List > df-ref | GIF version | ||
| Description: Define the set of all reflexive relationships over a base set. (Contributed by SF, 19-Feb-2015.) |
| Ref | Expression |
|---|---|
| df-ref | ⊢ Ref = {〈r, a〉 ∣ ∀x ∈ a xrx} |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | cref 5890 | . 2 class Ref | |
| 2 | vx | . . . . . 6 setvar x | |
| 3 | 2 | cv 1641 | . . . . 5 class x |
| 4 | vr | . . . . . 6 setvar r | |
| 5 | 4 | cv 1641 | . . . . 5 class r |
| 6 | 3, 3, 5 | wbr 4640 | . . . 4 wff xrx |
| 7 | va | . . . . 5 setvar a | |
| 8 | 7 | cv 1641 | . . . 4 class a |
| 9 | 6, 2, 8 | wral 2615 | . . 3 wff ∀x ∈ a xrx |
| 10 | 9, 4, 7 | copab 4623 | . 2 class {〈r, a〉 ∣ ∀x ∈ a xrx} |
| 11 | 1, 10 | wceq 1642 | 1 wff Ref = {〈r, a〉 ∣ ∀x ∈ a xrx} |
| Colors of variables: wff setvar class |
| This definition is referenced by: refex 5912 refrd 5927 refd 5928 |
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