| Step | 
						Hyp | 
						Ref | 
						Expression | 
					
						
							| 1 | 
							
								
							 | 
							bnj1280.1 | 
							 |-  B = { d | ( d C_ A /\ A. x e. d _pred ( x , A , R ) C_ d ) } | 
						
						
							| 2 | 
							
								
							 | 
							bnj1280.2 | 
							 |-  Y = <. x , ( f |` _pred ( x , A , R ) ) >.  | 
						
						
							| 3 | 
							
								
							 | 
							bnj1280.3 | 
							 |-  C = { f | E. d e. B ( f Fn d /\ A. x e. d ( f ` x ) = ( G ` Y ) ) } | 
						
						
							| 4 | 
							
								
							 | 
							bnj1280.4 | 
							 |-  D = ( dom g i^i dom h )  | 
						
						
							| 5 | 
							
								
							 | 
							bnj1280.5 | 
							 |-  E = { x e. D | ( g ` x ) =/= ( h ` x ) } | 
						
						
							| 6 | 
							
								
							 | 
							bnj1280.6 | 
							 |-  ( ph <-> ( R _FrSe A /\ g e. C /\ h e. C /\ ( g |` D ) =/= ( h |` D ) ) )  | 
						
						
							| 7 | 
							
								
							 | 
							bnj1280.7 | 
							 |-  ( ps <-> ( ph /\ x e. E /\ A. y e. E -. y R x ) )  | 
						
						
							| 8 | 
							
								
							 | 
							bnj1280.17 | 
							 |-  ( ps -> ( _pred ( x , A , R ) i^i E ) = (/) )  | 
						
						
							| 9 | 
							
								1 2 3 4 5 6 7
							 | 
							bnj1286 | 
							 |-  ( ps -> _pred ( x , A , R ) C_ D )  | 
						
						
							| 10 | 
							
								9
							 | 
							sseld | 
							 |-  ( ps -> ( z e. _pred ( x , A , R ) -> z e. D ) )  | 
						
						
							| 11 | 
							
								
							 | 
							disj1 | 
							 |-  ( ( _pred ( x , A , R ) i^i E ) = (/) <-> A. z ( z e. _pred ( x , A , R ) -> -. z e. E ) )  | 
						
						
							| 12 | 
							
								8 11
							 | 
							sylib | 
							 |-  ( ps -> A. z ( z e. _pred ( x , A , R ) -> -. z e. E ) )  | 
						
						
							| 13 | 
							
								12
							 | 
							19.21bi | 
							 |-  ( ps -> ( z e. _pred ( x , A , R ) -> -. z e. E ) )  | 
						
						
							| 14 | 
							
								
							 | 
							fveq2 | 
							 |-  ( x = z -> ( g ` x ) = ( g ` z ) )  | 
						
						
							| 15 | 
							
								
							 | 
							fveq2 | 
							 |-  ( x = z -> ( h ` x ) = ( h ` z ) )  | 
						
						
							| 16 | 
							
								14 15
							 | 
							neeq12d | 
							 |-  ( x = z -> ( ( g ` x ) =/= ( h ` x ) <-> ( g ` z ) =/= ( h ` z ) ) )  | 
						
						
							| 17 | 
							
								16 5
							 | 
							elrab2 | 
							 |-  ( z e. E <-> ( z e. D /\ ( g ` z ) =/= ( h ` z ) ) )  | 
						
						
							| 18 | 
							
								17
							 | 
							notbii | 
							 |-  ( -. z e. E <-> -. ( z e. D /\ ( g ` z ) =/= ( h ` z ) ) )  | 
						
						
							| 19 | 
							
								
							 | 
							imnan | 
							 |-  ( ( z e. D -> -. ( g ` z ) =/= ( h ` z ) ) <-> -. ( z e. D /\ ( g ` z ) =/= ( h ` z ) ) )  | 
						
						
							| 20 | 
							
								
							 | 
							nne | 
							 |-  ( -. ( g ` z ) =/= ( h ` z ) <-> ( g ` z ) = ( h ` z ) )  | 
						
						
							| 21 | 
							
								20
							 | 
							imbi2i | 
							 |-  ( ( z e. D -> -. ( g ` z ) =/= ( h ` z ) ) <-> ( z e. D -> ( g ` z ) = ( h ` z ) ) )  | 
						
						
							| 22 | 
							
								18 19 21
							 | 
							3bitr2i | 
							 |-  ( -. z e. E <-> ( z e. D -> ( g ` z ) = ( h ` z ) ) )  | 
						
						
							| 23 | 
							
								13 22
							 | 
							imbitrdi | 
							 |-  ( ps -> ( z e. _pred ( x , A , R ) -> ( z e. D -> ( g ` z ) = ( h ` z ) ) ) )  | 
						
						
							| 24 | 
							
								10 23
							 | 
							mpdd | 
							 |-  ( ps -> ( z e. _pred ( x , A , R ) -> ( g ` z ) = ( h ` z ) ) )  | 
						
						
							| 25 | 
							
								24
							 | 
							imp | 
							 |-  ( ( ps /\ z e. _pred ( x , A , R ) ) -> ( g ` z ) = ( h ` z ) )  | 
						
						
							| 26 | 
							
								
							 | 
							fvres | 
							 |-  ( z e. D -> ( ( g |` D ) ` z ) = ( g ` z ) )  | 
						
						
							| 27 | 
							
								10 26
							 | 
							syl6 | 
							 |-  ( ps -> ( z e. _pred ( x , A , R ) -> ( ( g |` D ) ` z ) = ( g ` z ) ) )  | 
						
						
							| 28 | 
							
								27
							 | 
							imp | 
							 |-  ( ( ps /\ z e. _pred ( x , A , R ) ) -> ( ( g |` D ) ` z ) = ( g ` z ) )  | 
						
						
							| 29 | 
							
								
							 | 
							fvres | 
							 |-  ( z e. D -> ( ( h |` D ) ` z ) = ( h ` z ) )  | 
						
						
							| 30 | 
							
								10 29
							 | 
							syl6 | 
							 |-  ( ps -> ( z e. _pred ( x , A , R ) -> ( ( h |` D ) ` z ) = ( h ` z ) ) )  | 
						
						
							| 31 | 
							
								30
							 | 
							imp | 
							 |-  ( ( ps /\ z e. _pred ( x , A , R ) ) -> ( ( h |` D ) ` z ) = ( h ` z ) )  | 
						
						
							| 32 | 
							
								25 28 31
							 | 
							3eqtr4d | 
							 |-  ( ( ps /\ z e. _pred ( x , A , R ) ) -> ( ( g |` D ) ` z ) = ( ( h |` D ) ` z ) )  | 
						
						
							| 33 | 
							
								32
							 | 
							ralrimiva | 
							 |-  ( ps -> A. z e. _pred ( x , A , R ) ( ( g |` D ) ` z ) = ( ( h |` D ) ` z ) )  | 
						
						
							| 34 | 
							
								9
							 | 
							resabs1d | 
							 |-  ( ps -> ( ( g |` D ) |` _pred ( x , A , R ) ) = ( g |` _pred ( x , A , R ) ) )  | 
						
						
							| 35 | 
							
								9
							 | 
							resabs1d | 
							 |-  ( ps -> ( ( h |` D ) |` _pred ( x , A , R ) ) = ( h |` _pred ( x , A , R ) ) )  | 
						
						
							| 36 | 
							
								34 35
							 | 
							eqeq12d | 
							 |-  ( ps -> ( ( ( g |` D ) |` _pred ( x , A , R ) ) = ( ( h |` D ) |` _pred ( x , A , R ) ) <-> ( g |` _pred ( x , A , R ) ) = ( h |` _pred ( x , A , R ) ) ) )  | 
						
						
							| 37 | 
							
								1 2 3 4 5 6 7
							 | 
							bnj1256 | 
							 |-  ( ph -> E. d e. B g Fn d )  | 
						
						
							| 38 | 
							
								4
							 | 
							bnj1292 | 
							 |-  D C_ dom g  | 
						
						
							| 39 | 
							
								
							 | 
							fndm | 
							 |-  ( g Fn d -> dom g = d )  | 
						
						
							| 40 | 
							
								38 39
							 | 
							sseqtrid | 
							 |-  ( g Fn d -> D C_ d )  | 
						
						
							| 41 | 
							
								
							 | 
							fnssres | 
							 |-  ( ( g Fn d /\ D C_ d ) -> ( g |` D ) Fn D )  | 
						
						
							| 42 | 
							
								40 41
							 | 
							mpdan | 
							 |-  ( g Fn d -> ( g |` D ) Fn D )  | 
						
						
							| 43 | 
							
								37 42
							 | 
							bnj31 | 
							 |-  ( ph -> E. d e. B ( g |` D ) Fn D )  | 
						
						
							| 44 | 
							
								43
							 | 
							bnj1265 | 
							 |-  ( ph -> ( g |` D ) Fn D )  | 
						
						
							| 45 | 
							
								7 44
							 | 
							bnj835 | 
							 |-  ( ps -> ( g |` D ) Fn D )  | 
						
						
							| 46 | 
							
								1 2 3 4 5 6 7
							 | 
							bnj1259 | 
							 |-  ( ph -> E. d e. B h Fn d )  | 
						
						
							| 47 | 
							
								4
							 | 
							bnj1293 | 
							 |-  D C_ dom h  | 
						
						
							| 48 | 
							
								
							 | 
							fndm | 
							 |-  ( h Fn d -> dom h = d )  | 
						
						
							| 49 | 
							
								47 48
							 | 
							sseqtrid | 
							 |-  ( h Fn d -> D C_ d )  | 
						
						
							| 50 | 
							
								
							 | 
							fnssres | 
							 |-  ( ( h Fn d /\ D C_ d ) -> ( h |` D ) Fn D )  | 
						
						
							| 51 | 
							
								49 50
							 | 
							mpdan | 
							 |-  ( h Fn d -> ( h |` D ) Fn D )  | 
						
						
							| 52 | 
							
								46 51
							 | 
							bnj31 | 
							 |-  ( ph -> E. d e. B ( h |` D ) Fn D )  | 
						
						
							| 53 | 
							
								52
							 | 
							bnj1265 | 
							 |-  ( ph -> ( h |` D ) Fn D )  | 
						
						
							| 54 | 
							
								7 53
							 | 
							bnj835 | 
							 |-  ( ps -> ( h |` D ) Fn D )  | 
						
						
							| 55 | 
							
								
							 | 
							fvreseq | 
							 |-  ( ( ( ( g |` D ) Fn D /\ ( h |` D ) Fn D ) /\ _pred ( x , A , R ) C_ D ) -> ( ( ( g |` D ) |` _pred ( x , A , R ) ) = ( ( h |` D ) |` _pred ( x , A , R ) ) <-> A. z e. _pred ( x , A , R ) ( ( g |` D ) ` z ) = ( ( h |` D ) ` z ) ) )  | 
						
						
							| 56 | 
							
								45 54 9 55
							 | 
							syl21anc | 
							 |-  ( ps -> ( ( ( g |` D ) |` _pred ( x , A , R ) ) = ( ( h |` D ) |` _pred ( x , A , R ) ) <-> A. z e. _pred ( x , A , R ) ( ( g |` D ) ` z ) = ( ( h |` D ) ` z ) ) )  | 
						
						
							| 57 | 
							
								36 56
							 | 
							bitr3d | 
							 |-  ( ps -> ( ( g |` _pred ( x , A , R ) ) = ( h |` _pred ( x , A , R ) ) <-> A. z e. _pred ( x , A , R ) ( ( g |` D ) ` z ) = ( ( h |` D ) ` z ) ) )  | 
						
						
							| 58 | 
							
								33 57
							 | 
							mpbird | 
							 |-  ( ps -> ( g |` _pred ( x , A , R ) ) = ( h |` _pred ( x , A , R ) ) )  |