Metamath Proof Explorer


Theorem rnqmap

Description: The range of the quotient map is the quotient carrier. It lets us replace quotient-carrier reasoning by map/range reasoning (and conversely) via df-qmap and dfqs2 . (Contributed by Peter Mazsa, 12-Feb-2026)

Ref Expression
Assertion rnqmap
|- ran QMap R = ( dom R /. R )

Proof

Step Hyp Ref Expression
1 df-qmap
 |-  QMap R = ( x e. dom R |-> [ x ] R )
2 1 rneqi
 |-  ran QMap R = ran ( x e. dom R |-> [ x ] R )
3 dfqs2
 |-  ( dom R /. R ) = ran ( x e. dom R |-> [ x ] R )
4 2 3 eqtr4i
 |-  ran QMap R = ( dom R /. R )