| Step | 
						Hyp | 
						Ref | 
						Expression | 
					
						
							| 1 | 
							
								
							 | 
							wfrlem13OLD.1 | 
							⊢ 𝑅  We  𝐴  | 
						
						
							| 2 | 
							
								
							 | 
							wfrlem13OLD.2 | 
							⊢ 𝑅  Se  𝐴  | 
						
						
							| 3 | 
							
								
							 | 
							wfrlem13OLD.3 | 
							⊢ 𝐹  =  wrecs ( 𝑅 ,  𝐴 ,  𝐺 )  | 
						
						
							| 4 | 
							
								
							 | 
							wfrlem13OLD.4 | 
							⊢ 𝐶  =  ( 𝐹  ∪  { 〈 𝑧 ,  ( 𝐺 ‘ ( 𝐹  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑧 ) ) ) 〉 } )  | 
						
						
							| 5 | 
							
								1 2 3 4
							 | 
							wfrlem13OLD | 
							⊢ ( 𝑧  ∈  ( 𝐴  ∖  dom  𝐹 )  →  𝐶  Fn  ( dom  𝐹  ∪  { 𝑧 } ) )  | 
						
						
							| 6 | 
							
								5
							 | 
							adantr | 
							⊢ ( ( 𝑧  ∈  ( 𝐴  ∖  dom  𝐹 )  ∧  Pred ( 𝑅 ,  ( 𝐴  ∖  dom  𝐹 ) ,  𝑧 )  =  ∅ )  →  𝐶  Fn  ( dom  𝐹  ∪  { 𝑧 } ) )  | 
						
						
							| 7 | 
							
								1 3
							 | 
							wfrlem10OLD | 
							⊢ ( ( 𝑧  ∈  ( 𝐴  ∖  dom  𝐹 )  ∧  Pred ( 𝑅 ,  ( 𝐴  ∖  dom  𝐹 ) ,  𝑧 )  =  ∅ )  →  Pred ( 𝑅 ,  𝐴 ,  𝑧 )  =  dom  𝐹 )  | 
						
						
							| 8 | 
							
								
							 | 
							eldifi | 
							⊢ ( 𝑧  ∈  ( 𝐴  ∖  dom  𝐹 )  →  𝑧  ∈  𝐴 )  | 
						
						
							| 9 | 
							
								
							 | 
							setlikespec | 
							⊢ ( ( 𝑧  ∈  𝐴  ∧  𝑅  Se  𝐴 )  →  Pred ( 𝑅 ,  𝐴 ,  𝑧 )  ∈  V )  | 
						
						
							| 10 | 
							
								8 2 9
							 | 
							sylancl | 
							⊢ ( 𝑧  ∈  ( 𝐴  ∖  dom  𝐹 )  →  Pred ( 𝑅 ,  𝐴 ,  𝑧 )  ∈  V )  | 
						
						
							| 11 | 
							
								10
							 | 
							adantr | 
							⊢ ( ( 𝑧  ∈  ( 𝐴  ∖  dom  𝐹 )  ∧  Pred ( 𝑅 ,  ( 𝐴  ∖  dom  𝐹 ) ,  𝑧 )  =  ∅ )  →  Pred ( 𝑅 ,  𝐴 ,  𝑧 )  ∈  V )  | 
						
						
							| 12 | 
							
								7 11
							 | 
							eqeltrrd | 
							⊢ ( ( 𝑧  ∈  ( 𝐴  ∖  dom  𝐹 )  ∧  Pred ( 𝑅 ,  ( 𝐴  ∖  dom  𝐹 ) ,  𝑧 )  =  ∅ )  →  dom  𝐹  ∈  V )  | 
						
						
							| 13 | 
							
								
							 | 
							snex | 
							⊢ { 𝑧 }  ∈  V  | 
						
						
							| 14 | 
							
								
							 | 
							unexg | 
							⊢ ( ( dom  𝐹  ∈  V  ∧  { 𝑧 }  ∈  V )  →  ( dom  𝐹  ∪  { 𝑧 } )  ∈  V )  | 
						
						
							| 15 | 
							
								13 14
							 | 
							mpan2 | 
							⊢ ( dom  𝐹  ∈  V  →  ( dom  𝐹  ∪  { 𝑧 } )  ∈  V )  | 
						
						
							| 16 | 
							
								
							 | 
							fnex | 
							⊢ ( ( 𝐶  Fn  ( dom  𝐹  ∪  { 𝑧 } )  ∧  ( dom  𝐹  ∪  { 𝑧 } )  ∈  V )  →  𝐶  ∈  V )  | 
						
						
							| 17 | 
							
								15 16
							 | 
							sylan2 | 
							⊢ ( ( 𝐶  Fn  ( dom  𝐹  ∪  { 𝑧 } )  ∧  dom  𝐹  ∈  V )  →  𝐶  ∈  V )  | 
						
						
							| 18 | 
							
								6 12 17
							 | 
							syl2anc | 
							⊢ ( ( 𝑧  ∈  ( 𝐴  ∖  dom  𝐹 )  ∧  Pred ( 𝑅 ,  ( 𝐴  ∖  dom  𝐹 ) ,  𝑧 )  =  ∅ )  →  𝐶  ∈  V )  | 
						
						
							| 19 | 
							
								12 13 14
							 | 
							sylancl | 
							⊢ ( ( 𝑧  ∈  ( 𝐴  ∖  dom  𝐹 )  ∧  Pred ( 𝑅 ,  ( 𝐴  ∖  dom  𝐹 ) ,  𝑧 )  =  ∅ )  →  ( dom  𝐹  ∪  { 𝑧 } )  ∈  V )  | 
						
						
							| 20 | 
							
								3
							 | 
							wfrdmssOLD | 
							⊢ dom  𝐹  ⊆  𝐴  | 
						
						
							| 21 | 
							
								8
							 | 
							snssd | 
							⊢ ( 𝑧  ∈  ( 𝐴  ∖  dom  𝐹 )  →  { 𝑧 }  ⊆  𝐴 )  | 
						
						
							| 22 | 
							
								
							 | 
							unss | 
							⊢ ( ( dom  𝐹  ⊆  𝐴  ∧  { 𝑧 }  ⊆  𝐴 )  ↔  ( dom  𝐹  ∪  { 𝑧 } )  ⊆  𝐴 )  | 
						
						
							| 23 | 
							
								22
							 | 
							biimpi | 
							⊢ ( ( dom  𝐹  ⊆  𝐴  ∧  { 𝑧 }  ⊆  𝐴 )  →  ( dom  𝐹  ∪  { 𝑧 } )  ⊆  𝐴 )  | 
						
						
							| 24 | 
							
								20 21 23
							 | 
							sylancr | 
							⊢ ( 𝑧  ∈  ( 𝐴  ∖  dom  𝐹 )  →  ( dom  𝐹  ∪  { 𝑧 } )  ⊆  𝐴 )  | 
						
						
							| 25 | 
							
								24
							 | 
							adantr | 
							⊢ ( ( 𝑧  ∈  ( 𝐴  ∖  dom  𝐹 )  ∧  Pred ( 𝑅 ,  ( 𝐴  ∖  dom  𝐹 ) ,  𝑧 )  =  ∅ )  →  ( dom  𝐹  ∪  { 𝑧 } )  ⊆  𝐴 )  | 
						
						
							| 26 | 
							
								
							 | 
							elun | 
							⊢ ( 𝑦  ∈  ( dom  𝐹  ∪  { 𝑧 } )  ↔  ( 𝑦  ∈  dom  𝐹  ∨  𝑦  ∈  { 𝑧 } ) )  | 
						
						
							| 27 | 
							
								
							 | 
							velsn | 
							⊢ ( 𝑦  ∈  { 𝑧 }  ↔  𝑦  =  𝑧 )  | 
						
						
							| 28 | 
							
								27
							 | 
							orbi2i | 
							⊢ ( ( 𝑦  ∈  dom  𝐹  ∨  𝑦  ∈  { 𝑧 } )  ↔  ( 𝑦  ∈  dom  𝐹  ∨  𝑦  =  𝑧 ) )  | 
						
						
							| 29 | 
							
								26 28
							 | 
							bitri | 
							⊢ ( 𝑦  ∈  ( dom  𝐹  ∪  { 𝑧 } )  ↔  ( 𝑦  ∈  dom  𝐹  ∨  𝑦  =  𝑧 ) )  | 
						
						
							| 30 | 
							
								3
							 | 
							wfrdmclOLD | 
							⊢ ( 𝑦  ∈  dom  𝐹  →  Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  dom  𝐹 )  | 
						
						
							| 31 | 
							
								
							 | 
							ssun3 | 
							⊢ ( Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  dom  𝐹  →  Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  ( dom  𝐹  ∪  { 𝑧 } ) )  | 
						
						
							| 32 | 
							
								30 31
							 | 
							syl | 
							⊢ ( 𝑦  ∈  dom  𝐹  →  Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  ( dom  𝐹  ∪  { 𝑧 } ) )  | 
						
						
							| 33 | 
							
								32
							 | 
							a1i | 
							⊢ ( ( 𝑧  ∈  ( 𝐴  ∖  dom  𝐹 )  ∧  Pred ( 𝑅 ,  ( 𝐴  ∖  dom  𝐹 ) ,  𝑧 )  =  ∅ )  →  ( 𝑦  ∈  dom  𝐹  →  Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  ( dom  𝐹  ∪  { 𝑧 } ) ) )  | 
						
						
							| 34 | 
							
								
							 | 
							ssun1 | 
							⊢ dom  𝐹  ⊆  ( dom  𝐹  ∪  { 𝑧 } )  | 
						
						
							| 35 | 
							
								7 34
							 | 
							eqsstrdi | 
							⊢ ( ( 𝑧  ∈  ( 𝐴  ∖  dom  𝐹 )  ∧  Pred ( 𝑅 ,  ( 𝐴  ∖  dom  𝐹 ) ,  𝑧 )  =  ∅ )  →  Pred ( 𝑅 ,  𝐴 ,  𝑧 )  ⊆  ( dom  𝐹  ∪  { 𝑧 } ) )  | 
						
						
							| 36 | 
							
								
							 | 
							predeq3 | 
							⊢ ( 𝑦  =  𝑧  →  Pred ( 𝑅 ,  𝐴 ,  𝑦 )  =  Pred ( 𝑅 ,  𝐴 ,  𝑧 ) )  | 
						
						
							| 37 | 
							
								36
							 | 
							sseq1d | 
							⊢ ( 𝑦  =  𝑧  →  ( Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  ( dom  𝐹  ∪  { 𝑧 } )  ↔  Pred ( 𝑅 ,  𝐴 ,  𝑧 )  ⊆  ( dom  𝐹  ∪  { 𝑧 } ) ) )  | 
						
						
							| 38 | 
							
								35 37
							 | 
							syl5ibrcom | 
							⊢ ( ( 𝑧  ∈  ( 𝐴  ∖  dom  𝐹 )  ∧  Pred ( 𝑅 ,  ( 𝐴  ∖  dom  𝐹 ) ,  𝑧 )  =  ∅ )  →  ( 𝑦  =  𝑧  →  Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  ( dom  𝐹  ∪  { 𝑧 } ) ) )  | 
						
						
							| 39 | 
							
								33 38
							 | 
							jaod | 
							⊢ ( ( 𝑧  ∈  ( 𝐴  ∖  dom  𝐹 )  ∧  Pred ( 𝑅 ,  ( 𝐴  ∖  dom  𝐹 ) ,  𝑧 )  =  ∅ )  →  ( ( 𝑦  ∈  dom  𝐹  ∨  𝑦  =  𝑧 )  →  Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  ( dom  𝐹  ∪  { 𝑧 } ) ) )  | 
						
						
							| 40 | 
							
								29 39
							 | 
							biimtrid | 
							⊢ ( ( 𝑧  ∈  ( 𝐴  ∖  dom  𝐹 )  ∧  Pred ( 𝑅 ,  ( 𝐴  ∖  dom  𝐹 ) ,  𝑧 )  =  ∅ )  →  ( 𝑦  ∈  ( dom  𝐹  ∪  { 𝑧 } )  →  Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  ( dom  𝐹  ∪  { 𝑧 } ) ) )  | 
						
						
							| 41 | 
							
								40
							 | 
							ralrimiv | 
							⊢ ( ( 𝑧  ∈  ( 𝐴  ∖  dom  𝐹 )  ∧  Pred ( 𝑅 ,  ( 𝐴  ∖  dom  𝐹 ) ,  𝑧 )  =  ∅ )  →  ∀ 𝑦  ∈  ( dom  𝐹  ∪  { 𝑧 } ) Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  ( dom  𝐹  ∪  { 𝑧 } ) )  | 
						
						
							| 42 | 
							
								25 41
							 | 
							jca | 
							⊢ ( ( 𝑧  ∈  ( 𝐴  ∖  dom  𝐹 )  ∧  Pred ( 𝑅 ,  ( 𝐴  ∖  dom  𝐹 ) ,  𝑧 )  =  ∅ )  →  ( ( dom  𝐹  ∪  { 𝑧 } )  ⊆  𝐴  ∧  ∀ 𝑦  ∈  ( dom  𝐹  ∪  { 𝑧 } ) Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  ( dom  𝐹  ∪  { 𝑧 } ) ) )  | 
						
						
							| 43 | 
							
								1 2 3 4
							 | 
							wfrlem14OLD | 
							⊢ ( 𝑧  ∈  ( 𝐴  ∖  dom  𝐹 )  →  ( 𝑦  ∈  ( dom  𝐹  ∪  { 𝑧 } )  →  ( 𝐶 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝐶  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) )  | 
						
						
							| 44 | 
							
								43
							 | 
							ralrimiv | 
							⊢ ( 𝑧  ∈  ( 𝐴  ∖  dom  𝐹 )  →  ∀ 𝑦  ∈  ( dom  𝐹  ∪  { 𝑧 } ) ( 𝐶 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝐶  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) )  | 
						
						
							| 45 | 
							
								44
							 | 
							adantr | 
							⊢ ( ( 𝑧  ∈  ( 𝐴  ∖  dom  𝐹 )  ∧  Pred ( 𝑅 ,  ( 𝐴  ∖  dom  𝐹 ) ,  𝑧 )  =  ∅ )  →  ∀ 𝑦  ∈  ( dom  𝐹  ∪  { 𝑧 } ) ( 𝐶 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝐶  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) )  | 
						
						
							| 46 | 
							
								6 42 45
							 | 
							3jca | 
							⊢ ( ( 𝑧  ∈  ( 𝐴  ∖  dom  𝐹 )  ∧  Pred ( 𝑅 ,  ( 𝐴  ∖  dom  𝐹 ) ,  𝑧 )  =  ∅ )  →  ( 𝐶  Fn  ( dom  𝐹  ∪  { 𝑧 } )  ∧  ( ( dom  𝐹  ∪  { 𝑧 } )  ⊆  𝐴  ∧  ∀ 𝑦  ∈  ( dom  𝐹  ∪  { 𝑧 } ) Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  ( dom  𝐹  ∪  { 𝑧 } ) )  ∧  ∀ 𝑦  ∈  ( dom  𝐹  ∪  { 𝑧 } ) ( 𝐶 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝐶  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) )  | 
						
						
							| 47 | 
							
								
							 | 
							fneq2 | 
							⊢ ( 𝑥  =  ( dom  𝐹  ∪  { 𝑧 } )  →  ( 𝐶  Fn  𝑥  ↔  𝐶  Fn  ( dom  𝐹  ∪  { 𝑧 } ) ) )  | 
						
						
							| 48 | 
							
								
							 | 
							sseq1 | 
							⊢ ( 𝑥  =  ( dom  𝐹  ∪  { 𝑧 } )  →  ( 𝑥  ⊆  𝐴  ↔  ( dom  𝐹  ∪  { 𝑧 } )  ⊆  𝐴 ) )  | 
						
						
							| 49 | 
							
								
							 | 
							sseq2 | 
							⊢ ( 𝑥  =  ( dom  𝐹  ∪  { 𝑧 } )  →  ( Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥  ↔  Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  ( dom  𝐹  ∪  { 𝑧 } ) ) )  | 
						
						
							| 50 | 
							
								49
							 | 
							raleqbi1dv | 
							⊢ ( 𝑥  =  ( dom  𝐹  ∪  { 𝑧 } )  →  ( ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥  ↔  ∀ 𝑦  ∈  ( dom  𝐹  ∪  { 𝑧 } ) Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  ( dom  𝐹  ∪  { 𝑧 } ) ) )  | 
						
						
							| 51 | 
							
								48 50
							 | 
							anbi12d | 
							⊢ ( 𝑥  =  ( dom  𝐹  ∪  { 𝑧 } )  →  ( ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ↔  ( ( dom  𝐹  ∪  { 𝑧 } )  ⊆  𝐴  ∧  ∀ 𝑦  ∈  ( dom  𝐹  ∪  { 𝑧 } ) Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  ( dom  𝐹  ∪  { 𝑧 } ) ) ) )  | 
						
						
							| 52 | 
							
								
							 | 
							raleq | 
							⊢ ( 𝑥  =  ( dom  𝐹  ∪  { 𝑧 } )  →  ( ∀ 𝑦  ∈  𝑥 ( 𝐶 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝐶  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) )  ↔  ∀ 𝑦  ∈  ( dom  𝐹  ∪  { 𝑧 } ) ( 𝐶 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝐶  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) )  | 
						
						
							| 53 | 
							
								47 51 52
							 | 
							3anbi123d | 
							⊢ ( 𝑥  =  ( dom  𝐹  ∪  { 𝑧 } )  →  ( ( 𝐶  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝐶 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝐶  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) )  ↔  ( 𝐶  Fn  ( dom  𝐹  ∪  { 𝑧 } )  ∧  ( ( dom  𝐹  ∪  { 𝑧 } )  ⊆  𝐴  ∧  ∀ 𝑦  ∈  ( dom  𝐹  ∪  { 𝑧 } ) Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  ( dom  𝐹  ∪  { 𝑧 } ) )  ∧  ∀ 𝑦  ∈  ( dom  𝐹  ∪  { 𝑧 } ) ( 𝐶 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝐶  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) ) )  | 
						
						
							| 54 | 
							
								19 46 53
							 | 
							spcedv | 
							⊢ ( ( 𝑧  ∈  ( 𝐴  ∖  dom  𝐹 )  ∧  Pred ( 𝑅 ,  ( 𝐴  ∖  dom  𝐹 ) ,  𝑧 )  =  ∅ )  →  ∃ 𝑥 ( 𝐶  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝐶 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝐶  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) )  | 
						
						
							| 55 | 
							
								
							 | 
							fneq1 | 
							⊢ ( 𝑓  =  𝐶  →  ( 𝑓  Fn  𝑥  ↔  𝐶  Fn  𝑥 ) )  | 
						
						
							| 56 | 
							
								
							 | 
							fveq1 | 
							⊢ ( 𝑓  =  𝐶  →  ( 𝑓 ‘ 𝑦 )  =  ( 𝐶 ‘ 𝑦 ) )  | 
						
						
							| 57 | 
							
								
							 | 
							reseq1 | 
							⊢ ( 𝑓  =  𝐶  →  ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) )  =  ( 𝐶  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) )  | 
						
						
							| 58 | 
							
								57
							 | 
							fveq2d | 
							⊢ ( 𝑓  =  𝐶  →  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) )  =  ( 𝐺 ‘ ( 𝐶  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) )  | 
						
						
							| 59 | 
							
								56 58
							 | 
							eqeq12d | 
							⊢ ( 𝑓  =  𝐶  →  ( ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) )  ↔  ( 𝐶 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝐶  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) )  | 
						
						
							| 60 | 
							
								59
							 | 
							ralbidv | 
							⊢ ( 𝑓  =  𝐶  →  ( ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) )  ↔  ∀ 𝑦  ∈  𝑥 ( 𝐶 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝐶  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) )  | 
						
						
							| 61 | 
							
								55 60
							 | 
							3anbi13d | 
							⊢ ( 𝑓  =  𝐶  →  ( ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) )  ↔  ( 𝐶  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝐶 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝐶  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) ) )  | 
						
						
							| 62 | 
							
								61
							 | 
							exbidv | 
							⊢ ( 𝑓  =  𝐶  →  ( ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) )  ↔  ∃ 𝑥 ( 𝐶  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝐶 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝐶  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) ) )  | 
						
						
							| 63 | 
							
								18 54 62
							 | 
							elabd | 
							⊢ ( ( 𝑧  ∈  ( 𝐴  ∖  dom  𝐹 )  ∧  Pred ( 𝑅 ,  ( 𝐴  ∖  dom  𝐹 ) ,  𝑧 )  =  ∅ )  →  𝐶  ∈  { 𝑓  ∣  ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) } )  |