| Step | 
						Hyp | 
						Ref | 
						Expression | 
					
						
							| 1 | 
							
								
							 | 
							wfrlem17OLD.1 | 
							⊢ 𝑅  We  𝐴  | 
						
						
							| 2 | 
							
								
							 | 
							wfrlem17OLD.2 | 
							⊢ 𝑅  Se  𝐴  | 
						
						
							| 3 | 
							
								
							 | 
							wfrlem17OLD.3 | 
							⊢ 𝐹  =  wrecs ( 𝑅 ,  𝐴 ,  𝐺 )  | 
						
						
							| 4 | 
							
								1 2 3
							 | 
							wfrfunOLD | 
							⊢ Fun  𝐹  | 
						
						
							| 5 | 
							
								
							 | 
							funfvop | 
							⊢ ( ( Fun  𝐹  ∧  𝑋  ∈  dom  𝐹 )  →  〈 𝑋 ,  ( 𝐹 ‘ 𝑋 ) 〉  ∈  𝐹 )  | 
						
						
							| 6 | 
							
								4 5
							 | 
							mpan | 
							⊢ ( 𝑋  ∈  dom  𝐹  →  〈 𝑋 ,  ( 𝐹 ‘ 𝑋 ) 〉  ∈  𝐹 )  | 
						
						
							| 7 | 
							
								
							 | 
							dfwrecsOLD | 
							⊢ wrecs ( 𝑅 ,  𝐴 ,  𝐺 )  =  ∪  { 𝑓  ∣  ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) }  | 
						
						
							| 8 | 
							
								3 7
							 | 
							eqtri | 
							⊢ 𝐹  =  ∪  { 𝑓  ∣  ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) }  | 
						
						
							| 9 | 
							
								8
							 | 
							eleq2i | 
							⊢ ( 〈 𝑋 ,  ( 𝐹 ‘ 𝑋 ) 〉  ∈  𝐹  ↔  〈 𝑋 ,  ( 𝐹 ‘ 𝑋 ) 〉  ∈  ∪  { 𝑓  ∣  ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) } )  | 
						
						
							| 10 | 
							
								
							 | 
							eluni | 
							⊢ ( 〈 𝑋 ,  ( 𝐹 ‘ 𝑋 ) 〉  ∈  ∪  { 𝑓  ∣  ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) }  ↔  ∃ 𝑔 ( 〈 𝑋 ,  ( 𝐹 ‘ 𝑋 ) 〉  ∈  𝑔  ∧  𝑔  ∈  { 𝑓  ∣  ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) } ) )  | 
						
						
							| 11 | 
							
								9 10
							 | 
							bitri | 
							⊢ ( 〈 𝑋 ,  ( 𝐹 ‘ 𝑋 ) 〉  ∈  𝐹  ↔  ∃ 𝑔 ( 〈 𝑋 ,  ( 𝐹 ‘ 𝑋 ) 〉  ∈  𝑔  ∧  𝑔  ∈  { 𝑓  ∣  ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) } ) )  | 
						
						
							| 12 | 
							
								6 11
							 | 
							sylib | 
							⊢ ( 𝑋  ∈  dom  𝐹  →  ∃ 𝑔 ( 〈 𝑋 ,  ( 𝐹 ‘ 𝑋 ) 〉  ∈  𝑔  ∧  𝑔  ∈  { 𝑓  ∣  ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) } ) )  | 
						
						
							| 13 | 
							
								
							 | 
							simprr | 
							⊢ ( ( 𝑋  ∈  dom  𝐹  ∧  ( 〈 𝑋 ,  ( 𝐹 ‘ 𝑋 ) 〉  ∈  𝑔  ∧  𝑔  ∈  { 𝑓  ∣  ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) } ) )  →  𝑔  ∈  { 𝑓  ∣  ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) } )  | 
						
						
							| 14 | 
							
								
							 | 
							eqid | 
							⊢ { 𝑓  ∣  ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) }  =  { 𝑓  ∣  ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) }  | 
						
						
							| 15 | 
							
								
							 | 
							vex | 
							⊢ 𝑔  ∈  V  | 
						
						
							| 16 | 
							
								14 15
							 | 
							wfrlem3OLDa | 
							⊢ ( 𝑔  ∈  { 𝑓  ∣  ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) }  ↔  ∃ 𝑧 ( 𝑔  Fn  𝑧  ∧  ( 𝑧  ⊆  𝐴  ∧  ∀ 𝑤  ∈  𝑧 Pred ( 𝑅 ,  𝐴 ,  𝑤 )  ⊆  𝑧 )  ∧  ∀ 𝑤  ∈  𝑧 ( 𝑔 ‘ 𝑤 )  =  ( 𝐺 ‘ ( 𝑔  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑤 ) ) ) ) )  | 
						
						
							| 17 | 
							
								13 16
							 | 
							sylib | 
							⊢ ( ( 𝑋  ∈  dom  𝐹  ∧  ( 〈 𝑋 ,  ( 𝐹 ‘ 𝑋 ) 〉  ∈  𝑔  ∧  𝑔  ∈  { 𝑓  ∣  ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) } ) )  →  ∃ 𝑧 ( 𝑔  Fn  𝑧  ∧  ( 𝑧  ⊆  𝐴  ∧  ∀ 𝑤  ∈  𝑧 Pred ( 𝑅 ,  𝐴 ,  𝑤 )  ⊆  𝑧 )  ∧  ∀ 𝑤  ∈  𝑧 ( 𝑔 ‘ 𝑤 )  =  ( 𝐺 ‘ ( 𝑔  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑤 ) ) ) ) )  | 
						
						
							| 18 | 
							
								
							 | 
							3simpa | 
							⊢ ( ( 𝑔  Fn  𝑧  ∧  ( 𝑧  ⊆  𝐴  ∧  ∀ 𝑤  ∈  𝑧 Pred ( 𝑅 ,  𝐴 ,  𝑤 )  ⊆  𝑧 )  ∧  ∀ 𝑤  ∈  𝑧 ( 𝑔 ‘ 𝑤 )  =  ( 𝐺 ‘ ( 𝑔  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑤 ) ) ) )  →  ( 𝑔  Fn  𝑧  ∧  ( 𝑧  ⊆  𝐴  ∧  ∀ 𝑤  ∈  𝑧 Pred ( 𝑅 ,  𝐴 ,  𝑤 )  ⊆  𝑧 ) ) )  | 
						
						
							| 19 | 
							
								
							 | 
							simprlr | 
							⊢ ( ( 𝑋  ∈  dom  𝐹  ∧  ( ( 〈 𝑋 ,  ( 𝐹 ‘ 𝑋 ) 〉  ∈  𝑔  ∧  𝑔  ∈  { 𝑓  ∣  ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) } )  ∧  ( 𝑔  Fn  𝑧  ∧  ( 𝑧  ⊆  𝐴  ∧  ∀ 𝑤  ∈  𝑧 Pred ( 𝑅 ,  𝐴 ,  𝑤 )  ⊆  𝑧 ) ) ) )  →  𝑔  ∈  { 𝑓  ∣  ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) } )  | 
						
						
							| 20 | 
							
								
							 | 
							elssuni | 
							⊢ ( 𝑔  ∈  { 𝑓  ∣  ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) }  →  𝑔  ⊆  ∪  { 𝑓  ∣  ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) } )  | 
						
						
							| 21 | 
							
								20 8
							 | 
							sseqtrrdi | 
							⊢ ( 𝑔  ∈  { 𝑓  ∣  ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) }  →  𝑔  ⊆  𝐹 )  | 
						
						
							| 22 | 
							
								19 21
							 | 
							syl | 
							⊢ ( ( 𝑋  ∈  dom  𝐹  ∧  ( ( 〈 𝑋 ,  ( 𝐹 ‘ 𝑋 ) 〉  ∈  𝑔  ∧  𝑔  ∈  { 𝑓  ∣  ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) } )  ∧  ( 𝑔  Fn  𝑧  ∧  ( 𝑧  ⊆  𝐴  ∧  ∀ 𝑤  ∈  𝑧 Pred ( 𝑅 ,  𝐴 ,  𝑤 )  ⊆  𝑧 ) ) ) )  →  𝑔  ⊆  𝐹 )  | 
						
						
							| 23 | 
							
								
							 | 
							predeq3 | 
							⊢ ( 𝑤  =  𝑋  →  Pred ( 𝑅 ,  𝐴 ,  𝑤 )  =  Pred ( 𝑅 ,  𝐴 ,  𝑋 ) )  | 
						
						
							| 24 | 
							
								23
							 | 
							sseq1d | 
							⊢ ( 𝑤  =  𝑋  →  ( Pred ( 𝑅 ,  𝐴 ,  𝑤 )  ⊆  𝑧  ↔  Pred ( 𝑅 ,  𝐴 ,  𝑋 )  ⊆  𝑧 ) )  | 
						
						
							| 25 | 
							
								
							 | 
							simprrr | 
							⊢ ( ( ( 〈 𝑋 ,  ( 𝐹 ‘ 𝑋 ) 〉  ∈  𝑔  ∧  𝑔  ∈  { 𝑓  ∣  ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) } )  ∧  ( 𝑔  Fn  𝑧  ∧  ( 𝑧  ⊆  𝐴  ∧  ∀ 𝑤  ∈  𝑧 Pred ( 𝑅 ,  𝐴 ,  𝑤 )  ⊆  𝑧 ) ) )  →  ∀ 𝑤  ∈  𝑧 Pred ( 𝑅 ,  𝐴 ,  𝑤 )  ⊆  𝑧 )  | 
						
						
							| 26 | 
							
								25
							 | 
							adantl | 
							⊢ ( ( 𝑋  ∈  dom  𝐹  ∧  ( ( 〈 𝑋 ,  ( 𝐹 ‘ 𝑋 ) 〉  ∈  𝑔  ∧  𝑔  ∈  { 𝑓  ∣  ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) } )  ∧  ( 𝑔  Fn  𝑧  ∧  ( 𝑧  ⊆  𝐴  ∧  ∀ 𝑤  ∈  𝑧 Pred ( 𝑅 ,  𝐴 ,  𝑤 )  ⊆  𝑧 ) ) ) )  →  ∀ 𝑤  ∈  𝑧 Pred ( 𝑅 ,  𝐴 ,  𝑤 )  ⊆  𝑧 )  | 
						
						
							| 27 | 
							
								
							 | 
							simprll | 
							⊢ ( ( 𝑋  ∈  dom  𝐹  ∧  ( ( 〈 𝑋 ,  ( 𝐹 ‘ 𝑋 ) 〉  ∈  𝑔  ∧  𝑔  ∈  { 𝑓  ∣  ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) } )  ∧  ( 𝑔  Fn  𝑧  ∧  ( 𝑧  ⊆  𝐴  ∧  ∀ 𝑤  ∈  𝑧 Pred ( 𝑅 ,  𝐴 ,  𝑤 )  ⊆  𝑧 ) ) ) )  →  〈 𝑋 ,  ( 𝐹 ‘ 𝑋 ) 〉  ∈  𝑔 )  | 
						
						
							| 28 | 
							
								
							 | 
							df-br | 
							⊢ ( 𝑋 𝑔 ( 𝐹 ‘ 𝑋 )  ↔  〈 𝑋 ,  ( 𝐹 ‘ 𝑋 ) 〉  ∈  𝑔 )  | 
						
						
							| 29 | 
							
								27 28
							 | 
							sylibr | 
							⊢ ( ( 𝑋  ∈  dom  𝐹  ∧  ( ( 〈 𝑋 ,  ( 𝐹 ‘ 𝑋 ) 〉  ∈  𝑔  ∧  𝑔  ∈  { 𝑓  ∣  ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) } )  ∧  ( 𝑔  Fn  𝑧  ∧  ( 𝑧  ⊆  𝐴  ∧  ∀ 𝑤  ∈  𝑧 Pred ( 𝑅 ,  𝐴 ,  𝑤 )  ⊆  𝑧 ) ) ) )  →  𝑋 𝑔 ( 𝐹 ‘ 𝑋 ) )  | 
						
						
							| 30 | 
							
								
							 | 
							fvex | 
							⊢ ( 𝐹 ‘ 𝑋 )  ∈  V  | 
						
						
							| 31 | 
							
								
							 | 
							breldmg | 
							⊢ ( ( 𝑋  ∈  dom  𝐹  ∧  ( 𝐹 ‘ 𝑋 )  ∈  V  ∧  𝑋 𝑔 ( 𝐹 ‘ 𝑋 ) )  →  𝑋  ∈  dom  𝑔 )  | 
						
						
							| 32 | 
							
								30 31
							 | 
							mp3an2 | 
							⊢ ( ( 𝑋  ∈  dom  𝐹  ∧  𝑋 𝑔 ( 𝐹 ‘ 𝑋 ) )  →  𝑋  ∈  dom  𝑔 )  | 
						
						
							| 33 | 
							
								29 32
							 | 
							syldan | 
							⊢ ( ( 𝑋  ∈  dom  𝐹  ∧  ( ( 〈 𝑋 ,  ( 𝐹 ‘ 𝑋 ) 〉  ∈  𝑔  ∧  𝑔  ∈  { 𝑓  ∣  ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) } )  ∧  ( 𝑔  Fn  𝑧  ∧  ( 𝑧  ⊆  𝐴  ∧  ∀ 𝑤  ∈  𝑧 Pred ( 𝑅 ,  𝐴 ,  𝑤 )  ⊆  𝑧 ) ) ) )  →  𝑋  ∈  dom  𝑔 )  | 
						
						
							| 34 | 
							
								
							 | 
							simprrl | 
							⊢ ( ( 𝑋  ∈  dom  𝐹  ∧  ( ( 〈 𝑋 ,  ( 𝐹 ‘ 𝑋 ) 〉  ∈  𝑔  ∧  𝑔  ∈  { 𝑓  ∣  ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) } )  ∧  ( 𝑔  Fn  𝑧  ∧  ( 𝑧  ⊆  𝐴  ∧  ∀ 𝑤  ∈  𝑧 Pred ( 𝑅 ,  𝐴 ,  𝑤 )  ⊆  𝑧 ) ) ) )  →  𝑔  Fn  𝑧 )  | 
						
						
							| 35 | 
							
								34
							 | 
							fndmd | 
							⊢ ( ( 𝑋  ∈  dom  𝐹  ∧  ( ( 〈 𝑋 ,  ( 𝐹 ‘ 𝑋 ) 〉  ∈  𝑔  ∧  𝑔  ∈  { 𝑓  ∣  ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) } )  ∧  ( 𝑔  Fn  𝑧  ∧  ( 𝑧  ⊆  𝐴  ∧  ∀ 𝑤  ∈  𝑧 Pred ( 𝑅 ,  𝐴 ,  𝑤 )  ⊆  𝑧 ) ) ) )  →  dom  𝑔  =  𝑧 )  | 
						
						
							| 36 | 
							
								33 35
							 | 
							eleqtrd | 
							⊢ ( ( 𝑋  ∈  dom  𝐹  ∧  ( ( 〈 𝑋 ,  ( 𝐹 ‘ 𝑋 ) 〉  ∈  𝑔  ∧  𝑔  ∈  { 𝑓  ∣  ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) } )  ∧  ( 𝑔  Fn  𝑧  ∧  ( 𝑧  ⊆  𝐴  ∧  ∀ 𝑤  ∈  𝑧 Pred ( 𝑅 ,  𝐴 ,  𝑤 )  ⊆  𝑧 ) ) ) )  →  𝑋  ∈  𝑧 )  | 
						
						
							| 37 | 
							
								24 26 36
							 | 
							rspcdva | 
							⊢ ( ( 𝑋  ∈  dom  𝐹  ∧  ( ( 〈 𝑋 ,  ( 𝐹 ‘ 𝑋 ) 〉  ∈  𝑔  ∧  𝑔  ∈  { 𝑓  ∣  ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) } )  ∧  ( 𝑔  Fn  𝑧  ∧  ( 𝑧  ⊆  𝐴  ∧  ∀ 𝑤  ∈  𝑧 Pred ( 𝑅 ,  𝐴 ,  𝑤 )  ⊆  𝑧 ) ) ) )  →  Pred ( 𝑅 ,  𝐴 ,  𝑋 )  ⊆  𝑧 )  | 
						
						
							| 38 | 
							
								37 35
							 | 
							sseqtrrd | 
							⊢ ( ( 𝑋  ∈  dom  𝐹  ∧  ( ( 〈 𝑋 ,  ( 𝐹 ‘ 𝑋 ) 〉  ∈  𝑔  ∧  𝑔  ∈  { 𝑓  ∣  ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) } )  ∧  ( 𝑔  Fn  𝑧  ∧  ( 𝑧  ⊆  𝐴  ∧  ∀ 𝑤  ∈  𝑧 Pred ( 𝑅 ,  𝐴 ,  𝑤 )  ⊆  𝑧 ) ) ) )  →  Pred ( 𝑅 ,  𝐴 ,  𝑋 )  ⊆  dom  𝑔 )  | 
						
						
							| 39 | 
							
								
							 | 
							fun2ssres | 
							⊢ ( ( Fun  𝐹  ∧  𝑔  ⊆  𝐹  ∧  Pred ( 𝑅 ,  𝐴 ,  𝑋 )  ⊆  dom  𝑔 )  →  ( 𝐹  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑋 ) )  =  ( 𝑔  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑋 ) ) )  | 
						
						
							| 40 | 
							
								4 22 38 39
							 | 
							mp3an2i | 
							⊢ ( ( 𝑋  ∈  dom  𝐹  ∧  ( ( 〈 𝑋 ,  ( 𝐹 ‘ 𝑋 ) 〉  ∈  𝑔  ∧  𝑔  ∈  { 𝑓  ∣  ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) } )  ∧  ( 𝑔  Fn  𝑧  ∧  ( 𝑧  ⊆  𝐴  ∧  ∀ 𝑤  ∈  𝑧 Pred ( 𝑅 ,  𝐴 ,  𝑤 )  ⊆  𝑧 ) ) ) )  →  ( 𝐹  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑋 ) )  =  ( 𝑔  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑋 ) ) )  | 
						
						
							| 41 | 
							
								15
							 | 
							resex | 
							⊢ ( 𝑔  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑋 ) )  ∈  V  | 
						
						
							| 42 | 
							
								40 41
							 | 
							eqeltrdi | 
							⊢ ( ( 𝑋  ∈  dom  𝐹  ∧  ( ( 〈 𝑋 ,  ( 𝐹 ‘ 𝑋 ) 〉  ∈  𝑔  ∧  𝑔  ∈  { 𝑓  ∣  ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) } )  ∧  ( 𝑔  Fn  𝑧  ∧  ( 𝑧  ⊆  𝐴  ∧  ∀ 𝑤  ∈  𝑧 Pred ( 𝑅 ,  𝐴 ,  𝑤 )  ⊆  𝑧 ) ) ) )  →  ( 𝐹  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑋 ) )  ∈  V )  | 
						
						
							| 43 | 
							
								42
							 | 
							expr | 
							⊢ ( ( 𝑋  ∈  dom  𝐹  ∧  ( 〈 𝑋 ,  ( 𝐹 ‘ 𝑋 ) 〉  ∈  𝑔  ∧  𝑔  ∈  { 𝑓  ∣  ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) } ) )  →  ( ( 𝑔  Fn  𝑧  ∧  ( 𝑧  ⊆  𝐴  ∧  ∀ 𝑤  ∈  𝑧 Pred ( 𝑅 ,  𝐴 ,  𝑤 )  ⊆  𝑧 ) )  →  ( 𝐹  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑋 ) )  ∈  V ) )  | 
						
						
							| 44 | 
							
								18 43
							 | 
							syl5 | 
							⊢ ( ( 𝑋  ∈  dom  𝐹  ∧  ( 〈 𝑋 ,  ( 𝐹 ‘ 𝑋 ) 〉  ∈  𝑔  ∧  𝑔  ∈  { 𝑓  ∣  ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) } ) )  →  ( ( 𝑔  Fn  𝑧  ∧  ( 𝑧  ⊆  𝐴  ∧  ∀ 𝑤  ∈  𝑧 Pred ( 𝑅 ,  𝐴 ,  𝑤 )  ⊆  𝑧 )  ∧  ∀ 𝑤  ∈  𝑧 ( 𝑔 ‘ 𝑤 )  =  ( 𝐺 ‘ ( 𝑔  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑤 ) ) ) )  →  ( 𝐹  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑋 ) )  ∈  V ) )  | 
						
						
							| 45 | 
							
								44
							 | 
							exlimdv | 
							⊢ ( ( 𝑋  ∈  dom  𝐹  ∧  ( 〈 𝑋 ,  ( 𝐹 ‘ 𝑋 ) 〉  ∈  𝑔  ∧  𝑔  ∈  { 𝑓  ∣  ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) } ) )  →  ( ∃ 𝑧 ( 𝑔  Fn  𝑧  ∧  ( 𝑧  ⊆  𝐴  ∧  ∀ 𝑤  ∈  𝑧 Pred ( 𝑅 ,  𝐴 ,  𝑤 )  ⊆  𝑧 )  ∧  ∀ 𝑤  ∈  𝑧 ( 𝑔 ‘ 𝑤 )  =  ( 𝐺 ‘ ( 𝑔  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑤 ) ) ) )  →  ( 𝐹  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑋 ) )  ∈  V ) )  | 
						
						
							| 46 | 
							
								17 45
							 | 
							mpd | 
							⊢ ( ( 𝑋  ∈  dom  𝐹  ∧  ( 〈 𝑋 ,  ( 𝐹 ‘ 𝑋 ) 〉  ∈  𝑔  ∧  𝑔  ∈  { 𝑓  ∣  ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) } ) )  →  ( 𝐹  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑋 ) )  ∈  V )  | 
						
						
							| 47 | 
							
								12 46
							 | 
							exlimddv | 
							⊢ ( 𝑋  ∈  dom  𝐹  →  ( 𝐹  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑋 ) )  ∈  V )  |