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Metamath Proof Explorer


Theorem eqvreldmqs2

Description: Two ways to express comember equivalence relation on its domain quotient. (Contributed by Peter Mazsa, 30-Dec-2024)

Ref Expression
Assertion eqvreldmqs2 EqvRel E -1 A dom E -1 A / E -1 A = A EqvRel A A / A = A

Proof

Step Hyp Ref Expression
1 df-coels A = E -1 A
2 1 eqvreleqi EqvRel A EqvRel E -1 A
3 2 bicomi EqvRel E -1 A EqvRel A
4 dmqs1cosscnvepreseq dom E -1 A / E -1 A = A A / A = A
5 3 4 anbi12i EqvRel E -1 A dom E -1 A / E -1 A = A EqvRel A A / A = A