| Step | 
						Hyp | 
						Ref | 
						Expression | 
					
						
							| 1 | 
							
								
							 | 
							fzennn.1 | 
							 |-  G = ( rec ( ( x e. _V |-> ( x + 1 ) ) , 0 ) |` _om )  | 
						
						
							| 2 | 
							
								
							 | 
							oveq2 | 
							 |-  ( n = 0 -> ( 1 ... n ) = ( 1 ... 0 ) )  | 
						
						
							| 3 | 
							
								
							 | 
							fveq2 | 
							 |-  ( n = 0 -> ( `' G ` n ) = ( `' G ` 0 ) )  | 
						
						
							| 4 | 
							
								2 3
							 | 
							breq12d | 
							 |-  ( n = 0 -> ( ( 1 ... n ) ~~ ( `' G ` n ) <-> ( 1 ... 0 ) ~~ ( `' G ` 0 ) ) )  | 
						
						
							| 5 | 
							
								
							 | 
							oveq2 | 
							 |-  ( n = m -> ( 1 ... n ) = ( 1 ... m ) )  | 
						
						
							| 6 | 
							
								
							 | 
							fveq2 | 
							 |-  ( n = m -> ( `' G ` n ) = ( `' G ` m ) )  | 
						
						
							| 7 | 
							
								5 6
							 | 
							breq12d | 
							 |-  ( n = m -> ( ( 1 ... n ) ~~ ( `' G ` n ) <-> ( 1 ... m ) ~~ ( `' G ` m ) ) )  | 
						
						
							| 8 | 
							
								
							 | 
							oveq2 | 
							 |-  ( n = ( m + 1 ) -> ( 1 ... n ) = ( 1 ... ( m + 1 ) ) )  | 
						
						
							| 9 | 
							
								
							 | 
							fveq2 | 
							 |-  ( n = ( m + 1 ) -> ( `' G ` n ) = ( `' G ` ( m + 1 ) ) )  | 
						
						
							| 10 | 
							
								8 9
							 | 
							breq12d | 
							 |-  ( n = ( m + 1 ) -> ( ( 1 ... n ) ~~ ( `' G ` n ) <-> ( 1 ... ( m + 1 ) ) ~~ ( `' G ` ( m + 1 ) ) ) )  | 
						
						
							| 11 | 
							
								
							 | 
							oveq2 | 
							 |-  ( n = N -> ( 1 ... n ) = ( 1 ... N ) )  | 
						
						
							| 12 | 
							
								
							 | 
							fveq2 | 
							 |-  ( n = N -> ( `' G ` n ) = ( `' G ` N ) )  | 
						
						
							| 13 | 
							
								11 12
							 | 
							breq12d | 
							 |-  ( n = N -> ( ( 1 ... n ) ~~ ( `' G ` n ) <-> ( 1 ... N ) ~~ ( `' G ` N ) ) )  | 
						
						
							| 14 | 
							
								
							 | 
							0ex | 
							 |-  (/) e. _V  | 
						
						
							| 15 | 
							
								14
							 | 
							enref | 
							 |-  (/) ~~ (/)  | 
						
						
							| 16 | 
							
								
							 | 
							fz10 | 
							 |-  ( 1 ... 0 ) = (/)  | 
						
						
							| 17 | 
							
								
							 | 
							0z | 
							 |-  0 e. ZZ  | 
						
						
							| 18 | 
							
								17 1
							 | 
							om2uzf1oi | 
							 |-  G : _om -1-1-onto-> ( ZZ>= ` 0 )  | 
						
						
							| 19 | 
							
								
							 | 
							peano1 | 
							 |-  (/) e. _om  | 
						
						
							| 20 | 
							
								18 19
							 | 
							pm3.2i | 
							 |-  ( G : _om -1-1-onto-> ( ZZ>= ` 0 ) /\ (/) e. _om )  | 
						
						
							| 21 | 
							
								17 1
							 | 
							om2uz0i | 
							 |-  ( G ` (/) ) = 0  | 
						
						
							| 22 | 
							
								
							 | 
							f1ocnvfv | 
							 |-  ( ( G : _om -1-1-onto-> ( ZZ>= ` 0 ) /\ (/) e. _om ) -> ( ( G ` (/) ) = 0 -> ( `' G ` 0 ) = (/) ) )  | 
						
						
							| 23 | 
							
								20 21 22
							 | 
							mp2 | 
							 |-  ( `' G ` 0 ) = (/)  | 
						
						
							| 24 | 
							
								15 16 23
							 | 
							3brtr4i | 
							 |-  ( 1 ... 0 ) ~~ ( `' G ` 0 )  | 
						
						
							| 25 | 
							
								
							 | 
							simpr | 
							 |-  ( ( m e. NN0 /\ ( 1 ... m ) ~~ ( `' G ` m ) ) -> ( 1 ... m ) ~~ ( `' G ` m ) )  | 
						
						
							| 26 | 
							
								
							 | 
							ovex | 
							 |-  ( m + 1 ) e. _V  | 
						
						
							| 27 | 
							
								
							 | 
							fvex | 
							 |-  ( `' G ` m ) e. _V  | 
						
						
							| 28 | 
							
								
							 | 
							en2sn | 
							 |-  ( ( ( m + 1 ) e. _V /\ ( `' G ` m ) e. _V ) -> { ( m + 1 ) } ~~ { ( `' G ` m ) } ) | 
						
						
							| 29 | 
							
								26 27 28
							 | 
							mp2an | 
							 |-  { ( m + 1 ) } ~~ { ( `' G ` m ) } | 
						
						
							| 30 | 
							
								29
							 | 
							a1i | 
							 |-  ( ( m e. NN0 /\ ( 1 ... m ) ~~ ( `' G ` m ) ) -> { ( m + 1 ) } ~~ { ( `' G ` m ) } ) | 
						
						
							| 31 | 
							
								
							 | 
							fzp1disj | 
							 |-  ( ( 1 ... m ) i^i { ( m + 1 ) } ) = (/) | 
						
						
							| 32 | 
							
								31
							 | 
							a1i | 
							 |-  ( ( m e. NN0 /\ ( 1 ... m ) ~~ ( `' G ` m ) ) -> ( ( 1 ... m ) i^i { ( m + 1 ) } ) = (/) ) | 
						
						
							| 33 | 
							
								
							 | 
							f1ocnvdm | 
							 |-  ( ( G : _om -1-1-onto-> ( ZZ>= ` 0 ) /\ m e. ( ZZ>= ` 0 ) ) -> ( `' G ` m ) e. _om )  | 
						
						
							| 34 | 
							
								18 33
							 | 
							mpan | 
							 |-  ( m e. ( ZZ>= ` 0 ) -> ( `' G ` m ) e. _om )  | 
						
						
							| 35 | 
							
								
							 | 
							nn0uz | 
							 |-  NN0 = ( ZZ>= ` 0 )  | 
						
						
							| 36 | 
							
								34 35
							 | 
							eleq2s | 
							 |-  ( m e. NN0 -> ( `' G ` m ) e. _om )  | 
						
						
							| 37 | 
							
								
							 | 
							nnord | 
							 |-  ( ( `' G ` m ) e. _om -> Ord ( `' G ` m ) )  | 
						
						
							| 38 | 
							
								
							 | 
							ordirr | 
							 |-  ( Ord ( `' G ` m ) -> -. ( `' G ` m ) e. ( `' G ` m ) )  | 
						
						
							| 39 | 
							
								36 37 38
							 | 
							3syl | 
							 |-  ( m e. NN0 -> -. ( `' G ` m ) e. ( `' G ` m ) )  | 
						
						
							| 40 | 
							
								39
							 | 
							adantr | 
							 |-  ( ( m e. NN0 /\ ( 1 ... m ) ~~ ( `' G ` m ) ) -> -. ( `' G ` m ) e. ( `' G ` m ) )  | 
						
						
							| 41 | 
							
								
							 | 
							disjsn | 
							 |-  ( ( ( `' G ` m ) i^i { ( `' G ` m ) } ) = (/) <-> -. ( `' G ` m ) e. ( `' G ` m ) ) | 
						
						
							| 42 | 
							
								40 41
							 | 
							sylibr | 
							 |-  ( ( m e. NN0 /\ ( 1 ... m ) ~~ ( `' G ` m ) ) -> ( ( `' G ` m ) i^i { ( `' G ` m ) } ) = (/) ) | 
						
						
							| 43 | 
							
								
							 | 
							unen | 
							 |-  ( ( ( ( 1 ... m ) ~~ ( `' G ` m ) /\ { ( m + 1 ) } ~~ { ( `' G ` m ) } ) /\ ( ( ( 1 ... m ) i^i { ( m + 1 ) } ) = (/) /\ ( ( `' G ` m ) i^i { ( `' G ` m ) } ) = (/) ) ) -> ( ( 1 ... m ) u. { ( m + 1 ) } ) ~~ ( ( `' G ` m ) u. { ( `' G ` m ) } ) ) | 
						
						
							| 44 | 
							
								25 30 32 42 43
							 | 
							syl22anc | 
							 |-  ( ( m e. NN0 /\ ( 1 ... m ) ~~ ( `' G ` m ) ) -> ( ( 1 ... m ) u. { ( m + 1 ) } ) ~~ ( ( `' G ` m ) u. { ( `' G ` m ) } ) ) | 
						
						
							| 45 | 
							
								
							 | 
							1z | 
							 |-  1 e. ZZ  | 
						
						
							| 46 | 
							
								
							 | 
							1m1e0 | 
							 |-  ( 1 - 1 ) = 0  | 
						
						
							| 47 | 
							
								46
							 | 
							fveq2i | 
							 |-  ( ZZ>= ` ( 1 - 1 ) ) = ( ZZ>= ` 0 )  | 
						
						
							| 48 | 
							
								35 47
							 | 
							eqtr4i | 
							 |-  NN0 = ( ZZ>= ` ( 1 - 1 ) )  | 
						
						
							| 49 | 
							
								48
							 | 
							eleq2i | 
							 |-  ( m e. NN0 <-> m e. ( ZZ>= ` ( 1 - 1 ) ) )  | 
						
						
							| 50 | 
							
								49
							 | 
							biimpi | 
							 |-  ( m e. NN0 -> m e. ( ZZ>= ` ( 1 - 1 ) ) )  | 
						
						
							| 51 | 
							
								
							 | 
							fzsuc2 | 
							 |-  ( ( 1 e. ZZ /\ m e. ( ZZ>= ` ( 1 - 1 ) ) ) -> ( 1 ... ( m + 1 ) ) = ( ( 1 ... m ) u. { ( m + 1 ) } ) ) | 
						
						
							| 52 | 
							
								45 50 51
							 | 
							sylancr | 
							 |-  ( m e. NN0 -> ( 1 ... ( m + 1 ) ) = ( ( 1 ... m ) u. { ( m + 1 ) } ) ) | 
						
						
							| 53 | 
							
								52
							 | 
							adantr | 
							 |-  ( ( m e. NN0 /\ ( 1 ... m ) ~~ ( `' G ` m ) ) -> ( 1 ... ( m + 1 ) ) = ( ( 1 ... m ) u. { ( m + 1 ) } ) ) | 
						
						
							| 54 | 
							
								
							 | 
							peano2 | 
							 |-  ( ( `' G ` m ) e. _om -> suc ( `' G ` m ) e. _om )  | 
						
						
							| 55 | 
							
								36 54
							 | 
							syl | 
							 |-  ( m e. NN0 -> suc ( `' G ` m ) e. _om )  | 
						
						
							| 56 | 
							
								55 18
							 | 
							jctil | 
							 |-  ( m e. NN0 -> ( G : _om -1-1-onto-> ( ZZ>= ` 0 ) /\ suc ( `' G ` m ) e. _om ) )  | 
						
						
							| 57 | 
							
								17 1
							 | 
							om2uzsuci | 
							 |-  ( ( `' G ` m ) e. _om -> ( G ` suc ( `' G ` m ) ) = ( ( G ` ( `' G ` m ) ) + 1 ) )  | 
						
						
							| 58 | 
							
								36 57
							 | 
							syl | 
							 |-  ( m e. NN0 -> ( G ` suc ( `' G ` m ) ) = ( ( G ` ( `' G ` m ) ) + 1 ) )  | 
						
						
							| 59 | 
							
								35
							 | 
							eleq2i | 
							 |-  ( m e. NN0 <-> m e. ( ZZ>= ` 0 ) )  | 
						
						
							| 60 | 
							
								59
							 | 
							biimpi | 
							 |-  ( m e. NN0 -> m e. ( ZZ>= ` 0 ) )  | 
						
						
							| 61 | 
							
								
							 | 
							f1ocnvfv2 | 
							 |-  ( ( G : _om -1-1-onto-> ( ZZ>= ` 0 ) /\ m e. ( ZZ>= ` 0 ) ) -> ( G ` ( `' G ` m ) ) = m )  | 
						
						
							| 62 | 
							
								18 60 61
							 | 
							sylancr | 
							 |-  ( m e. NN0 -> ( G ` ( `' G ` m ) ) = m )  | 
						
						
							| 63 | 
							
								62
							 | 
							oveq1d | 
							 |-  ( m e. NN0 -> ( ( G ` ( `' G ` m ) ) + 1 ) = ( m + 1 ) )  | 
						
						
							| 64 | 
							
								58 63
							 | 
							eqtrd | 
							 |-  ( m e. NN0 -> ( G ` suc ( `' G ` m ) ) = ( m + 1 ) )  | 
						
						
							| 65 | 
							
								
							 | 
							f1ocnvfv | 
							 |-  ( ( G : _om -1-1-onto-> ( ZZ>= ` 0 ) /\ suc ( `' G ` m ) e. _om ) -> ( ( G ` suc ( `' G ` m ) ) = ( m + 1 ) -> ( `' G ` ( m + 1 ) ) = suc ( `' G ` m ) ) )  | 
						
						
							| 66 | 
							
								56 64 65
							 | 
							sylc | 
							 |-  ( m e. NN0 -> ( `' G ` ( m + 1 ) ) = suc ( `' G ` m ) )  | 
						
						
							| 67 | 
							
								66
							 | 
							adantr | 
							 |-  ( ( m e. NN0 /\ ( 1 ... m ) ~~ ( `' G ` m ) ) -> ( `' G ` ( m + 1 ) ) = suc ( `' G ` m ) )  | 
						
						
							| 68 | 
							
								
							 | 
							df-suc | 
							 |-  suc ( `' G ` m ) = ( ( `' G ` m ) u. { ( `' G ` m ) } ) | 
						
						
							| 69 | 
							
								67 68
							 | 
							eqtrdi | 
							 |-  ( ( m e. NN0 /\ ( 1 ... m ) ~~ ( `' G ` m ) ) -> ( `' G ` ( m + 1 ) ) = ( ( `' G ` m ) u. { ( `' G ` m ) } ) ) | 
						
						
							| 70 | 
							
								44 53 69
							 | 
							3brtr4d | 
							 |-  ( ( m e. NN0 /\ ( 1 ... m ) ~~ ( `' G ` m ) ) -> ( 1 ... ( m + 1 ) ) ~~ ( `' G ` ( m + 1 ) ) )  | 
						
						
							| 71 | 
							
								70
							 | 
							ex | 
							 |-  ( m e. NN0 -> ( ( 1 ... m ) ~~ ( `' G ` m ) -> ( 1 ... ( m + 1 ) ) ~~ ( `' G ` ( m + 1 ) ) ) )  | 
						
						
							| 72 | 
							
								4 7 10 13 24 71
							 | 
							nn0ind | 
							 |-  ( N e. NN0 -> ( 1 ... N ) ~~ ( `' G ` N ) )  |