| Step | Hyp | Ref | Expression | 
						
							| 1 |  | vex |  |-  z e. _V | 
						
							| 2 | 1 | elrn |  |-  ( z e. ran tpos F <-> E. w w tpos F z ) | 
						
							| 3 |  | vex |  |-  w e. _V | 
						
							| 4 | 3 1 | breldm |  |-  ( w tpos F z -> w e. dom tpos F ) | 
						
							| 5 |  | dmtpos |  |-  ( Rel dom F -> dom tpos F = `' dom F ) | 
						
							| 6 | 5 | eleq2d |  |-  ( Rel dom F -> ( w e. dom tpos F <-> w e. `' dom F ) ) | 
						
							| 7 | 4 6 | imbitrid |  |-  ( Rel dom F -> ( w tpos F z -> w e. `' dom F ) ) | 
						
							| 8 |  | relcnv |  |-  Rel `' dom F | 
						
							| 9 |  | elrel |  |-  ( ( Rel `' dom F /\ w e. `' dom F ) -> E. x E. y w = <. x , y >. ) | 
						
							| 10 | 8 9 | mpan |  |-  ( w e. `' dom F -> E. x E. y w = <. x , y >. ) | 
						
							| 11 | 7 10 | syl6 |  |-  ( Rel dom F -> ( w tpos F z -> E. x E. y w = <. x , y >. ) ) | 
						
							| 12 |  | breq1 |  |-  ( w = <. x , y >. -> ( w tpos F z <-> <. x , y >. tpos F z ) ) | 
						
							| 13 |  | brtpos |  |-  ( z e. _V -> ( <. x , y >. tpos F z <-> <. y , x >. F z ) ) | 
						
							| 14 | 13 | elv |  |-  ( <. x , y >. tpos F z <-> <. y , x >. F z ) | 
						
							| 15 | 12 14 | bitrdi |  |-  ( w = <. x , y >. -> ( w tpos F z <-> <. y , x >. F z ) ) | 
						
							| 16 |  | opex |  |-  <. y , x >. e. _V | 
						
							| 17 | 16 1 | brelrn |  |-  ( <. y , x >. F z -> z e. ran F ) | 
						
							| 18 | 15 17 | biimtrdi |  |-  ( w = <. x , y >. -> ( w tpos F z -> z e. ran F ) ) | 
						
							| 19 | 18 | exlimivv |  |-  ( E. x E. y w = <. x , y >. -> ( w tpos F z -> z e. ran F ) ) | 
						
							| 20 | 11 19 | syli |  |-  ( Rel dom F -> ( w tpos F z -> z e. ran F ) ) | 
						
							| 21 | 20 | exlimdv |  |-  ( Rel dom F -> ( E. w w tpos F z -> z e. ran F ) ) | 
						
							| 22 | 2 21 | biimtrid |  |-  ( Rel dom F -> ( z e. ran tpos F -> z e. ran F ) ) | 
						
							| 23 | 1 | elrn |  |-  ( z e. ran F <-> E. w w F z ) | 
						
							| 24 | 3 1 | breldm |  |-  ( w F z -> w e. dom F ) | 
						
							| 25 |  | elrel |  |-  ( ( Rel dom F /\ w e. dom F ) -> E. y E. x w = <. y , x >. ) | 
						
							| 26 | 25 | ex |  |-  ( Rel dom F -> ( w e. dom F -> E. y E. x w = <. y , x >. ) ) | 
						
							| 27 | 24 26 | syl5 |  |-  ( Rel dom F -> ( w F z -> E. y E. x w = <. y , x >. ) ) | 
						
							| 28 |  | breq1 |  |-  ( w = <. y , x >. -> ( w F z <-> <. y , x >. F z ) ) | 
						
							| 29 | 28 14 | bitr4di |  |-  ( w = <. y , x >. -> ( w F z <-> <. x , y >. tpos F z ) ) | 
						
							| 30 |  | opex |  |-  <. x , y >. e. _V | 
						
							| 31 | 30 1 | brelrn |  |-  ( <. x , y >. tpos F z -> z e. ran tpos F ) | 
						
							| 32 | 29 31 | biimtrdi |  |-  ( w = <. y , x >. -> ( w F z -> z e. ran tpos F ) ) | 
						
							| 33 | 32 | exlimivv |  |-  ( E. y E. x w = <. y , x >. -> ( w F z -> z e. ran tpos F ) ) | 
						
							| 34 | 27 33 | syli |  |-  ( Rel dom F -> ( w F z -> z e. ran tpos F ) ) | 
						
							| 35 | 34 | exlimdv |  |-  ( Rel dom F -> ( E. w w F z -> z e. ran tpos F ) ) | 
						
							| 36 | 23 35 | biimtrid |  |-  ( Rel dom F -> ( z e. ran F -> z e. ran tpos F ) ) | 
						
							| 37 | 22 36 | impbid |  |-  ( Rel dom F -> ( z e. ran tpos F <-> z e. ran F ) ) | 
						
							| 38 | 37 | eqrdv |  |-  ( Rel dom F -> ran tpos F = ran F ) |