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 -1 ran A = dom A

Proof

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