| Step | 
						Hyp | 
						Ref | 
						Expression | 
					
						
							| 1 | 
							
								
							 | 
							f1opw2.1 | 
							 |-  ( ph -> F : A -1-1-onto-> B )  | 
						
						
							| 2 | 
							
								
							 | 
							f1opw2.2 | 
							 |-  ( ph -> ( `' F " a ) e. _V )  | 
						
						
							| 3 | 
							
								
							 | 
							f1opw2.3 | 
							 |-  ( ph -> ( F " b ) e. _V )  | 
						
						
							| 4 | 
							
								
							 | 
							eqid | 
							 |-  ( b e. ~P A |-> ( F " b ) ) = ( b e. ~P A |-> ( F " b ) )  | 
						
						
							| 5 | 
							
								
							 | 
							imassrn | 
							 |-  ( F " b ) C_ ran F  | 
						
						
							| 6 | 
							
								
							 | 
							f1ofo | 
							 |-  ( F : A -1-1-onto-> B -> F : A -onto-> B )  | 
						
						
							| 7 | 
							
								1 6
							 | 
							syl | 
							 |-  ( ph -> F : A -onto-> B )  | 
						
						
							| 8 | 
							
								
							 | 
							forn | 
							 |-  ( F : A -onto-> B -> ran F = B )  | 
						
						
							| 9 | 
							
								7 8
							 | 
							syl | 
							 |-  ( ph -> ran F = B )  | 
						
						
							| 10 | 
							
								5 9
							 | 
							sseqtrid | 
							 |-  ( ph -> ( F " b ) C_ B )  | 
						
						
							| 11 | 
							
								3 10
							 | 
							elpwd | 
							 |-  ( ph -> ( F " b ) e. ~P B )  | 
						
						
							| 12 | 
							
								11
							 | 
							adantr | 
							 |-  ( ( ph /\ b e. ~P A ) -> ( F " b ) e. ~P B )  | 
						
						
							| 13 | 
							
								
							 | 
							imassrn | 
							 |-  ( `' F " a ) C_ ran `' F  | 
						
						
							| 14 | 
							
								
							 | 
							dfdm4 | 
							 |-  dom F = ran `' F  | 
						
						
							| 15 | 
							
								
							 | 
							f1odm | 
							 |-  ( F : A -1-1-onto-> B -> dom F = A )  | 
						
						
							| 16 | 
							
								1 15
							 | 
							syl | 
							 |-  ( ph -> dom F = A )  | 
						
						
							| 17 | 
							
								14 16
							 | 
							eqtr3id | 
							 |-  ( ph -> ran `' F = A )  | 
						
						
							| 18 | 
							
								13 17
							 | 
							sseqtrid | 
							 |-  ( ph -> ( `' F " a ) C_ A )  | 
						
						
							| 19 | 
							
								2 18
							 | 
							elpwd | 
							 |-  ( ph -> ( `' F " a ) e. ~P A )  | 
						
						
							| 20 | 
							
								19
							 | 
							adantr | 
							 |-  ( ( ph /\ a e. ~P B ) -> ( `' F " a ) e. ~P A )  | 
						
						
							| 21 | 
							
								
							 | 
							elpwi | 
							 |-  ( a e. ~P B -> a C_ B )  | 
						
						
							| 22 | 
							
								21
							 | 
							adantl | 
							 |-  ( ( b e. ~P A /\ a e. ~P B ) -> a C_ B )  | 
						
						
							| 23 | 
							
								
							 | 
							foimacnv | 
							 |-  ( ( F : A -onto-> B /\ a C_ B ) -> ( F " ( `' F " a ) ) = a )  | 
						
						
							| 24 | 
							
								7 22 23
							 | 
							syl2an | 
							 |-  ( ( ph /\ ( b e. ~P A /\ a e. ~P B ) ) -> ( F " ( `' F " a ) ) = a )  | 
						
						
							| 25 | 
							
								24
							 | 
							eqcomd | 
							 |-  ( ( ph /\ ( b e. ~P A /\ a e. ~P B ) ) -> a = ( F " ( `' F " a ) ) )  | 
						
						
							| 26 | 
							
								
							 | 
							imaeq2 | 
							 |-  ( b = ( `' F " a ) -> ( F " b ) = ( F " ( `' F " a ) ) )  | 
						
						
							| 27 | 
							
								26
							 | 
							eqeq2d | 
							 |-  ( b = ( `' F " a ) -> ( a = ( F " b ) <-> a = ( F " ( `' F " a ) ) ) )  | 
						
						
							| 28 | 
							
								25 27
							 | 
							syl5ibrcom | 
							 |-  ( ( ph /\ ( b e. ~P A /\ a e. ~P B ) ) -> ( b = ( `' F " a ) -> a = ( F " b ) ) )  | 
						
						
							| 29 | 
							
								
							 | 
							f1of1 | 
							 |-  ( F : A -1-1-onto-> B -> F : A -1-1-> B )  | 
						
						
							| 30 | 
							
								1 29
							 | 
							syl | 
							 |-  ( ph -> F : A -1-1-> B )  | 
						
						
							| 31 | 
							
								
							 | 
							elpwi | 
							 |-  ( b e. ~P A -> b C_ A )  | 
						
						
							| 32 | 
							
								31
							 | 
							adantr | 
							 |-  ( ( b e. ~P A /\ a e. ~P B ) -> b C_ A )  | 
						
						
							| 33 | 
							
								
							 | 
							f1imacnv | 
							 |-  ( ( F : A -1-1-> B /\ b C_ A ) -> ( `' F " ( F " b ) ) = b )  | 
						
						
							| 34 | 
							
								30 32 33
							 | 
							syl2an | 
							 |-  ( ( ph /\ ( b e. ~P A /\ a e. ~P B ) ) -> ( `' F " ( F " b ) ) = b )  | 
						
						
							| 35 | 
							
								34
							 | 
							eqcomd | 
							 |-  ( ( ph /\ ( b e. ~P A /\ a e. ~P B ) ) -> b = ( `' F " ( F " b ) ) )  | 
						
						
							| 36 | 
							
								
							 | 
							imaeq2 | 
							 |-  ( a = ( F " b ) -> ( `' F " a ) = ( `' F " ( F " b ) ) )  | 
						
						
							| 37 | 
							
								36
							 | 
							eqeq2d | 
							 |-  ( a = ( F " b ) -> ( b = ( `' F " a ) <-> b = ( `' F " ( F " b ) ) ) )  | 
						
						
							| 38 | 
							
								35 37
							 | 
							syl5ibrcom | 
							 |-  ( ( ph /\ ( b e. ~P A /\ a e. ~P B ) ) -> ( a = ( F " b ) -> b = ( `' F " a ) ) )  | 
						
						
							| 39 | 
							
								28 38
							 | 
							impbid | 
							 |-  ( ( ph /\ ( b e. ~P A /\ a e. ~P B ) ) -> ( b = ( `' F " a ) <-> a = ( F " b ) ) )  | 
						
						
							| 40 | 
							
								4 12 20 39
							 | 
							f1o2d | 
							 |-  ( ph -> ( b e. ~P A |-> ( F " b ) ) : ~P A -1-1-onto-> ~P B )  |