| Step | 
						Hyp | 
						Ref | 
						Expression | 
					
						
							| 1 | 
							
								
							 | 
							bnj929.1 | 
							⊢ ( 𝜑  ↔  ( 𝑓 ‘ ∅ )  =   pred ( 𝑋 ,  𝐴 ,  𝑅 ) )  | 
						
						
							| 2 | 
							
								
							 | 
							bnj929.4 | 
							⊢ ( 𝜑′  ↔  [ 𝑝  /  𝑛 ] 𝜑 )  | 
						
						
							| 3 | 
							
								
							 | 
							bnj929.7 | 
							⊢ ( 𝜑″  ↔  [ 𝐺  /  𝑓 ] 𝜑′ )  | 
						
						
							| 4 | 
							
								
							 | 
							bnj929.10 | 
							⊢ 𝐷  =  ( ω  ∖  { ∅ } )  | 
						
						
							| 5 | 
							
								
							 | 
							bnj929.13 | 
							⊢ 𝐺  =  ( 𝑓  ∪  { 〈 𝑛 ,  𝐶 〉 } )  | 
						
						
							| 6 | 
							
								
							 | 
							bnj929.50 | 
							⊢ 𝐶  ∈  V  | 
						
						
							| 7 | 
							
								
							 | 
							bnj645 | 
							⊢ ( ( 𝑛  ∈  𝐷  ∧  𝑝  =  suc  𝑛  ∧  𝑓  Fn  𝑛  ∧  𝜑 )  →  𝜑 )  | 
						
						
							| 8 | 
							
								
							 | 
							bnj334 | 
							⊢ ( ( 𝑛  ∈  𝐷  ∧  𝑝  =  suc  𝑛  ∧  𝑓  Fn  𝑛  ∧  𝜑 )  ↔  ( 𝑓  Fn  𝑛  ∧  𝑛  ∈  𝐷  ∧  𝑝  =  suc  𝑛  ∧  𝜑 ) )  | 
						
						
							| 9 | 
							
								
							 | 
							bnj257 | 
							⊢ ( ( 𝑓  Fn  𝑛  ∧  𝑛  ∈  𝐷  ∧  𝑝  =  suc  𝑛  ∧  𝜑 )  ↔  ( 𝑓  Fn  𝑛  ∧  𝑛  ∈  𝐷  ∧  𝜑  ∧  𝑝  =  suc  𝑛 ) )  | 
						
						
							| 10 | 
							
								8 9
							 | 
							bitri | 
							⊢ ( ( 𝑛  ∈  𝐷  ∧  𝑝  =  suc  𝑛  ∧  𝑓  Fn  𝑛  ∧  𝜑 )  ↔  ( 𝑓  Fn  𝑛  ∧  𝑛  ∈  𝐷  ∧  𝜑  ∧  𝑝  =  suc  𝑛 ) )  | 
						
						
							| 11 | 
							
								
							 | 
							bnj345 | 
							⊢ ( ( 𝑓  Fn  𝑛  ∧  𝑛  ∈  𝐷  ∧  𝜑  ∧  𝑝  =  suc  𝑛 )  ↔  ( 𝑝  =  suc  𝑛  ∧  𝑓  Fn  𝑛  ∧  𝑛  ∈  𝐷  ∧  𝜑 ) )  | 
						
						
							| 12 | 
							
								
							 | 
							bnj253 | 
							⊢ ( ( 𝑝  =  suc  𝑛  ∧  𝑓  Fn  𝑛  ∧  𝑛  ∈  𝐷  ∧  𝜑 )  ↔  ( ( 𝑝  =  suc  𝑛  ∧  𝑓  Fn  𝑛 )  ∧  𝑛  ∈  𝐷  ∧  𝜑 ) )  | 
						
						
							| 13 | 
							
								10 11 12
							 | 
							3bitri | 
							⊢ ( ( 𝑛  ∈  𝐷  ∧  𝑝  =  suc  𝑛  ∧  𝑓  Fn  𝑛  ∧  𝜑 )  ↔  ( ( 𝑝  =  suc  𝑛  ∧  𝑓  Fn  𝑛 )  ∧  𝑛  ∈  𝐷  ∧  𝜑 ) )  | 
						
						
							| 14 | 
							
								13
							 | 
							simp1bi | 
							⊢ ( ( 𝑛  ∈  𝐷  ∧  𝑝  =  suc  𝑛  ∧  𝑓  Fn  𝑛  ∧  𝜑 )  →  ( 𝑝  =  suc  𝑛  ∧  𝑓  Fn  𝑛 ) )  | 
						
						
							| 15 | 
							
								5 6
							 | 
							bnj927 | 
							⊢ ( ( 𝑝  =  suc  𝑛  ∧  𝑓  Fn  𝑛 )  →  𝐺  Fn  𝑝 )  | 
						
						
							| 16 | 
							
								15
							 | 
							fnfund | 
							⊢ ( ( 𝑝  =  suc  𝑛  ∧  𝑓  Fn  𝑛 )  →  Fun  𝐺 )  | 
						
						
							| 17 | 
							
								14 16
							 | 
							syl | 
							⊢ ( ( 𝑛  ∈  𝐷  ∧  𝑝  =  suc  𝑛  ∧  𝑓  Fn  𝑛  ∧  𝜑 )  →  Fun  𝐺 )  | 
						
						
							| 18 | 
							
								5
							 | 
							bnj931 | 
							⊢ 𝑓  ⊆  𝐺  | 
						
						
							| 19 | 
							
								18
							 | 
							a1i | 
							⊢ ( ( 𝑛  ∈  𝐷  ∧  𝑝  =  suc  𝑛  ∧  𝑓  Fn  𝑛  ∧  𝜑 )  →  𝑓  ⊆  𝐺 )  | 
						
						
							| 20 | 
							
								
							 | 
							bnj268 | 
							⊢ ( ( 𝑛  ∈  𝐷  ∧  𝑓  Fn  𝑛  ∧  𝑝  =  suc  𝑛  ∧  𝜑 )  ↔  ( 𝑛  ∈  𝐷  ∧  𝑝  =  suc  𝑛  ∧  𝑓  Fn  𝑛  ∧  𝜑 ) )  | 
						
						
							| 21 | 
							
								
							 | 
							bnj253 | 
							⊢ ( ( 𝑛  ∈  𝐷  ∧  𝑓  Fn  𝑛  ∧  𝑝  =  suc  𝑛  ∧  𝜑 )  ↔  ( ( 𝑛  ∈  𝐷  ∧  𝑓  Fn  𝑛 )  ∧  𝑝  =  suc  𝑛  ∧  𝜑 ) )  | 
						
						
							| 22 | 
							
								20 21
							 | 
							bitr3i | 
							⊢ ( ( 𝑛  ∈  𝐷  ∧  𝑝  =  suc  𝑛  ∧  𝑓  Fn  𝑛  ∧  𝜑 )  ↔  ( ( 𝑛  ∈  𝐷  ∧  𝑓  Fn  𝑛 )  ∧  𝑝  =  suc  𝑛  ∧  𝜑 ) )  | 
						
						
							| 23 | 
							
								22
							 | 
							simp1bi | 
							⊢ ( ( 𝑛  ∈  𝐷  ∧  𝑝  =  suc  𝑛  ∧  𝑓  Fn  𝑛  ∧  𝜑 )  →  ( 𝑛  ∈  𝐷  ∧  𝑓  Fn  𝑛 ) )  | 
						
						
							| 24 | 
							
								
							 | 
							fndm | 
							⊢ ( 𝑓  Fn  𝑛  →  dom  𝑓  =  𝑛 )  | 
						
						
							| 25 | 
							
								4
							 | 
							bnj529 | 
							⊢ ( 𝑛  ∈  𝐷  →  ∅  ∈  𝑛 )  | 
						
						
							| 26 | 
							
								
							 | 
							eleq2 | 
							⊢ ( dom  𝑓  =  𝑛  →  ( ∅  ∈  dom  𝑓  ↔  ∅  ∈  𝑛 ) )  | 
						
						
							| 27 | 
							
								26
							 | 
							biimpar | 
							⊢ ( ( dom  𝑓  =  𝑛  ∧  ∅  ∈  𝑛 )  →  ∅  ∈  dom  𝑓 )  | 
						
						
							| 28 | 
							
								24 25 27
							 | 
							syl2anr | 
							⊢ ( ( 𝑛  ∈  𝐷  ∧  𝑓  Fn  𝑛 )  →  ∅  ∈  dom  𝑓 )  | 
						
						
							| 29 | 
							
								23 28
							 | 
							syl | 
							⊢ ( ( 𝑛  ∈  𝐷  ∧  𝑝  =  suc  𝑛  ∧  𝑓  Fn  𝑛  ∧  𝜑 )  →  ∅  ∈  dom  𝑓 )  | 
						
						
							| 30 | 
							
								17 19 29
							 | 
							bnj1502 | 
							⊢ ( ( 𝑛  ∈  𝐷  ∧  𝑝  =  suc  𝑛  ∧  𝑓  Fn  𝑛  ∧  𝜑 )  →  ( 𝐺 ‘ ∅ )  =  ( 𝑓 ‘ ∅ ) )  | 
						
						
							| 31 | 
							
								5
							 | 
							bnj918 | 
							⊢ 𝐺  ∈  V  | 
						
						
							| 32 | 
							
								1 2 3 31
							 | 
							bnj934 | 
							⊢ ( ( 𝜑  ∧  ( 𝐺 ‘ ∅ )  =  ( 𝑓 ‘ ∅ ) )  →  𝜑″ )  | 
						
						
							| 33 | 
							
								7 30 32
							 | 
							syl2anc | 
							⊢ ( ( 𝑛  ∈  𝐷  ∧  𝑝  =  suc  𝑛  ∧  𝑓  Fn  𝑛  ∧  𝜑 )  →  𝜑″ )  |