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 |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | imadmrn | ||
2 | df-rn | ||
3 | 2 | imaeq2i | |
4 | dfdm4 | ||
5 | 1 3 4 | 3eqtr4i |