Metamath Proof Explorer


Theorem cnvimarndm

Description: The preimage of the range of a class is the domain of the class. (Contributed by Jeff Hankins, 15-Jul-2009)

Ref Expression
Assertion cnvimarndm ( 𝐴 “ ran 𝐴 ) = dom 𝐴

Proof

Step Hyp Ref Expression
1 imadmrn ( 𝐴 “ dom 𝐴 ) = ran 𝐴
2 df-rn ran 𝐴 = dom 𝐴
3 2 imaeq2i ( 𝐴 “ ran 𝐴 ) = ( 𝐴 “ dom 𝐴 )
4 dfdm4 dom 𝐴 = ran 𝐴
5 1 3 4 3eqtr4i ( 𝐴 “ ran 𝐴 ) = dom 𝐴