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Definition df-qs 7635
 Description: Define quotient set. 𝑅 is usually an equivalence relation. Definition of [Enderton] p. 58. (Contributed by NM, 23-Jul-1995.)
Assertion
Ref Expression
df-qs (𝐴 / 𝑅) = {𝑦 ∣ ∃𝑥𝐴 𝑦 = [𝑥]𝑅}
Distinct variable groups:   𝑥,𝑦,𝐴   𝑥,𝑅,𝑦

Detailed syntax breakdown of Definition df-qs
StepHypRef Expression
1 cA . . 3 class 𝐴
2 cR . . 3 class 𝑅
31, 2cqs 7628 . 2 class (𝐴 / 𝑅)
4 vy . . . . . 6 setvar 𝑦
54cv 1474 . . . . 5 class 𝑦
6 vx . . . . . . 7 setvar 𝑥
76cv 1474 . . . . . 6 class 𝑥
87, 2cec 7627 . . . . 5 class [𝑥]𝑅
95, 8wceq 1475 . . . 4 wff 𝑦 = [𝑥]𝑅
109, 6, 1wrex 2897 . . 3 wff 𝑥𝐴 𝑦 = [𝑥]𝑅
1110, 4cab 2596 . 2 class {𝑦 ∣ ∃𝑥𝐴 𝑦 = [𝑥]𝑅}
123, 11wceq 1475 1 wff (𝐴 / 𝑅) = {𝑦 ∣ ∃𝑥𝐴 𝑦 = [𝑥]𝑅}
 Colors of variables: wff setvar class This definition is referenced by:  qseq1  7683  qseq2  7684  elqsg  7685  qsexg  7692  uniqs  7694  snec  7697  qsinxp  7710  qliftf  7722  quslem  16026  pi1xfrf  22661  pi1cof  22667
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