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Metamath Proof Explorer

Theorem gimcnv

Description: The converse of a group isomorphism is a group isomorphism. (Contributed by Stefan O'Rear, 25-Jan-2015) (Revised by Mario Carneiro, 6-May-2015)

Ref Expression
Assertion gimcnv 
|- ( F e. ( S GrpIso T ) -> `' F e. ( T GrpIso S ) )

Proof

Step Hyp Ref Expression
1 eqid 
 |-  ( Base ` S ) = ( Base ` S )
2 eqid 
 |-  ( Base ` T ) = ( Base ` T )
3 1 2 ghmf 
 |-  ( F e. ( S GrpHom T ) -> F : ( Base ` S ) --> ( Base ` T ) )
4 frel 
 |-  ( F : ( Base ` S ) --> ( Base ` T ) -> Rel F )
5 dfrel2 
 |-  ( Rel F <-> `' `' F = F )
6 4 5 sylib 
 |-  ( F : ( Base ` S ) --> ( Base ` T ) -> `' `' F = F )
7 3 6 syl 
 |-  ( F e. ( S GrpHom T ) -> `' `' F = F )
8 id 
 |-  ( F e. ( S GrpHom T ) -> F e. ( S GrpHom T ) )
9 7 8 eqeltrd 
 |-  ( F e. ( S GrpHom T ) -> `' `' F e. ( S GrpHom T ) )
10 9 anim1ci 
 |-  ( ( F e. ( S GrpHom T ) /\ `' F e. ( T GrpHom S ) ) -> ( `' F e. ( T GrpHom S ) /\ `' `' F e. ( S GrpHom T ) ) )
11 isgim2 
 |-  ( F e. ( S GrpIso T ) <-> ( F e. ( S GrpHom T ) /\ `' F e. ( T GrpHom S ) ) )
12 isgim2 
 |-  ( `' F e. ( T GrpIso S ) <-> ( `' F e. ( T GrpHom S ) /\ `' `' F e. ( S GrpHom T ) ) )
13 10 11 12 3imtr4i 
 |-  ( F e. ( S GrpIso T ) -> `' F e. ( T GrpIso S ) )