Metamath Proof Explorer


Theorem ishmeo

Description: The predicate F is a homeomorphism between topology J and topology K . Criterion of BourbakiTop1 p. I.2. (Contributed by FL, 14-Feb-2007) (Revised by Mario Carneiro, 22-Aug-2015)

Ref Expression
Assertion ishmeo
|- ( F e. ( J Homeo K ) <-> ( F e. ( J Cn K ) /\ `' F e. ( K Cn J ) ) )

Proof

Step Hyp Ref Expression
1 cnveq
 |-  ( f = F -> `' f = `' F )
2 1 eleq1d
 |-  ( f = F -> ( `' f e. ( K Cn J ) <-> `' F e. ( K Cn J ) ) )
3 hmeofval
 |-  ( J Homeo K ) = { f e. ( J Cn K ) | `' f e. ( K Cn J ) }
4 2 3 elrab2
 |-  ( F e. ( J Homeo K ) <-> ( F e. ( J Cn K ) /\ `' F e. ( K Cn J ) ) )