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Mirrors > Home > MPE Home > Th. List > df-qs | Structured version Visualization version GIF version |
Description: Define quotient set. 𝑅 is usually an equivalence relation. Definition of [Enderton] p. 58. (Contributed by NM, 23-Jul-1995.) |
Ref | Expression |
---|---|
df-qs | ⊢ (𝐴 / 𝑅) = {𝑦 ∣ ∃𝑥 ∈ 𝐴 𝑦 = [𝑥]𝑅} |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | cA | . . 3 class 𝐴 | |
2 | cR | . . 3 class 𝑅 | |
3 | 1, 2 | cqs 7741 | . 2 class (𝐴 / 𝑅) |
4 | vy | . . . . . 6 setvar 𝑦 | |
5 | 4 | cv 1482 | . . . . 5 class 𝑦 |
6 | vx | . . . . . . 7 setvar 𝑥 | |
7 | 6 | cv 1482 | . . . . . 6 class 𝑥 |
8 | 7, 2 | cec 7740 | . . . . 5 class [𝑥]𝑅 |
9 | 5, 8 | wceq 1483 | . . . 4 wff 𝑦 = [𝑥]𝑅 |
10 | 9, 6, 1 | wrex 2913 | . . 3 wff ∃𝑥 ∈ 𝐴 𝑦 = [𝑥]𝑅 |
11 | 10, 4 | cab 2608 | . 2 class {𝑦 ∣ ∃𝑥 ∈ 𝐴 𝑦 = [𝑥]𝑅} |
12 | 3, 11 | wceq 1483 | 1 wff (𝐴 / 𝑅) = {𝑦 ∣ ∃𝑥 ∈ 𝐴 𝑦 = [𝑥]𝑅} |
Colors of variables: wff setvar class |
This definition is referenced by: qseq1 7796 qseq2 7797 elqsg 7798 qsexg 7805 uniqs 7807 snec 7810 qsinxp 7823 qliftf 7835 quslem 16203 pi1xfrf 22853 pi1cof 22859 qsss1 34053 qsresid 34096 uniqsALTV 34101 0qs 34133 |
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