| Step | 
						Hyp | 
						Ref | 
						Expression | 
					
						
							| 1 | 
							
								
							 | 
							bnj1018.1 | 
							⊢ ( 𝜑  ↔  ( 𝑓 ‘ ∅ )  =   pred ( 𝑋 ,  𝐴 ,  𝑅 ) )  | 
						
						
							| 2 | 
							
								
							 | 
							bnj1018.2 | 
							⊢ ( 𝜓  ↔  ∀ 𝑖  ∈  ω ( suc  𝑖  ∈  𝑛  →  ( 𝑓 ‘ suc  𝑖 )  =  ∪  𝑦  ∈  ( 𝑓 ‘ 𝑖 )  pred ( 𝑦 ,  𝐴 ,  𝑅 ) ) )  | 
						
						
							| 3 | 
							
								
							 | 
							bnj1018.3 | 
							⊢ ( 𝜒  ↔  ( 𝑛  ∈  𝐷  ∧  𝑓  Fn  𝑛  ∧  𝜑  ∧  𝜓 ) )  | 
						
						
							| 4 | 
							
								
							 | 
							bnj1018.4 | 
							⊢ ( 𝜃  ↔  ( 𝑅  FrSe  𝐴  ∧  𝑋  ∈  𝐴  ∧  𝑦  ∈   trCl ( 𝑋 ,  𝐴 ,  𝑅 )  ∧  𝑧  ∈   pred ( 𝑦 ,  𝐴 ,  𝑅 ) ) )  | 
						
						
							| 5 | 
							
								
							 | 
							bnj1018.5 | 
							⊢ ( 𝜏  ↔  ( 𝑚  ∈  ω  ∧  𝑛  =  suc  𝑚  ∧  𝑝  =  suc  𝑛 ) )  | 
						
						
							| 6 | 
							
								
							 | 
							bnj1018.7 | 
							⊢ ( 𝜑′  ↔  [ 𝑝  /  𝑛 ] 𝜑 )  | 
						
						
							| 7 | 
							
								
							 | 
							bnj1018.8 | 
							⊢ ( 𝜓′  ↔  [ 𝑝  /  𝑛 ] 𝜓 )  | 
						
						
							| 8 | 
							
								
							 | 
							bnj1018.9 | 
							⊢ ( 𝜒′  ↔  [ 𝑝  /  𝑛 ] 𝜒 )  | 
						
						
							| 9 | 
							
								
							 | 
							bnj1018.10 | 
							⊢ ( 𝜑″  ↔  [ 𝐺  /  𝑓 ] 𝜑′ )  | 
						
						
							| 10 | 
							
								
							 | 
							bnj1018.11 | 
							⊢ ( 𝜓″  ↔  [ 𝐺  /  𝑓 ] 𝜓′ )  | 
						
						
							| 11 | 
							
								
							 | 
							bnj1018.12 | 
							⊢ ( 𝜒″  ↔  [ 𝐺  /  𝑓 ] 𝜒′ )  | 
						
						
							| 12 | 
							
								
							 | 
							bnj1018.13 | 
							⊢ 𝐷  =  ( ω  ∖  { ∅ } )  | 
						
						
							| 13 | 
							
								
							 | 
							bnj1018.14 | 
							⊢ 𝐵  =  { 𝑓  ∣  ∃ 𝑛  ∈  𝐷 ( 𝑓  Fn  𝑛  ∧  𝜑  ∧  𝜓 ) }  | 
						
						
							| 14 | 
							
								
							 | 
							bnj1018.15 | 
							⊢ 𝐶  =  ∪  𝑦  ∈  ( 𝑓 ‘ 𝑚 )  pred ( 𝑦 ,  𝐴 ,  𝑅 )  | 
						
						
							| 15 | 
							
								
							 | 
							bnj1018.16 | 
							⊢ 𝐺  =  ( 𝑓  ∪  { 〈 𝑛 ,  𝐶 〉 } )  | 
						
						
							| 16 | 
							
								
							 | 
							bnj1018.26 | 
							⊢ ( 𝜒″  ↔  ( 𝑝  ∈  𝐷  ∧  𝐺  Fn  𝑝  ∧  𝜑″  ∧  𝜓″ ) )  | 
						
						
							| 17 | 
							
								
							 | 
							bnj1018.29 | 
							⊢ ( ( 𝜃  ∧  𝜒  ∧  𝜏  ∧  𝜂 )  →  𝜒″ )  | 
						
						
							| 18 | 
							
								
							 | 
							bnj1018.30 | 
							⊢ ( ( 𝜃  ∧  𝜒  ∧  𝜏  ∧  𝜂 )  →  ( 𝜒″  ∧  𝑖  ∈  ω  ∧  suc  𝑖  ∈  𝑝 ) )  | 
						
						
							| 19 | 
							
								
							 | 
							df-bnj17 | 
							⊢ ( ( 𝜃  ∧  𝜒  ∧  𝜂  ∧  ∃ 𝑝 𝜏 )  ↔  ( ( 𝜃  ∧  𝜒  ∧  𝜂 )  ∧  ∃ 𝑝 𝜏 ) )  | 
						
						
							| 20 | 
							
								
							 | 
							bnj258 | 
							⊢ ( ( 𝜃  ∧  𝜒  ∧  𝜏  ∧  𝜂 )  ↔  ( ( 𝜃  ∧  𝜒  ∧  𝜂 )  ∧  𝜏 ) )  | 
						
						
							| 21 | 
							
								20 17
							 | 
							sylbir | 
							⊢ ( ( ( 𝜃  ∧  𝜒  ∧  𝜂 )  ∧  𝜏 )  →  𝜒″ )  | 
						
						
							| 22 | 
							
								21
							 | 
							ex | 
							⊢ ( ( 𝜃  ∧  𝜒  ∧  𝜂 )  →  ( 𝜏  →  𝜒″ ) )  | 
						
						
							| 23 | 
							
								22
							 | 
							eximdv | 
							⊢ ( ( 𝜃  ∧  𝜒  ∧  𝜂 )  →  ( ∃ 𝑝 𝜏  →  ∃ 𝑝 𝜒″ ) )  | 
						
						
							| 24 | 
							
								3 8 11 13 15
							 | 
							bnj985 | 
							⊢ ( 𝐺  ∈  𝐵  ↔  ∃ 𝑝 𝜒″ )  | 
						
						
							| 25 | 
							
								23 24
							 | 
							imbitrrdi | 
							⊢ ( ( 𝜃  ∧  𝜒  ∧  𝜂 )  →  ( ∃ 𝑝 𝜏  →  𝐺  ∈  𝐵 ) )  | 
						
						
							| 26 | 
							
								25
							 | 
							imp | 
							⊢ ( ( ( 𝜃  ∧  𝜒  ∧  𝜂 )  ∧  ∃ 𝑝 𝜏 )  →  𝐺  ∈  𝐵 )  | 
						
						
							| 27 | 
							
								19 26
							 | 
							sylbi | 
							⊢ ( ( 𝜃  ∧  𝜒  ∧  𝜂  ∧  ∃ 𝑝 𝜏 )  →  𝐺  ∈  𝐵 )  | 
						
						
							| 28 | 
							
								
							 | 
							bnj1019 | 
							⊢ ( ∃ 𝑝 ( 𝜃  ∧  𝜒  ∧  𝜏  ∧  𝜂 )  ↔  ( 𝜃  ∧  𝜒  ∧  𝜂  ∧  ∃ 𝑝 𝜏 ) )  | 
						
						
							| 29 | 
							
								18
							 | 
							simp3d | 
							⊢ ( ( 𝜃  ∧  𝜒  ∧  𝜏  ∧  𝜂 )  →  suc  𝑖  ∈  𝑝 )  | 
						
						
							| 30 | 
							
								16
							 | 
							bnj1235 | 
							⊢ ( 𝜒″  →  𝐺  Fn  𝑝 )  | 
						
						
							| 31 | 
							
								
							 | 
							fndm | 
							⊢ ( 𝐺  Fn  𝑝  →  dom  𝐺  =  𝑝 )  | 
						
						
							| 32 | 
							
								17 30 31
							 | 
							3syl | 
							⊢ ( ( 𝜃  ∧  𝜒  ∧  𝜏  ∧  𝜂 )  →  dom  𝐺  =  𝑝 )  | 
						
						
							| 33 | 
							
								29 32
							 | 
							eleqtrrd | 
							⊢ ( ( 𝜃  ∧  𝜒  ∧  𝜏  ∧  𝜂 )  →  suc  𝑖  ∈  dom  𝐺 )  | 
						
						
							| 34 | 
							
								33
							 | 
							exlimiv | 
							⊢ ( ∃ 𝑝 ( 𝜃  ∧  𝜒  ∧  𝜏  ∧  𝜂 )  →  suc  𝑖  ∈  dom  𝐺 )  | 
						
						
							| 35 | 
							
								28 34
							 | 
							sylbir | 
							⊢ ( ( 𝜃  ∧  𝜒  ∧  𝜂  ∧  ∃ 𝑝 𝜏 )  →  suc  𝑖  ∈  dom  𝐺 )  | 
						
						
							| 36 | 
							
								15
							 | 
							bnj918 | 
							⊢ 𝐺  ∈  V  | 
						
						
							| 37 | 
							
								
							 | 
							vex | 
							⊢ 𝑖  ∈  V  | 
						
						
							| 38 | 
							
								37
							 | 
							sucex | 
							⊢ suc  𝑖  ∈  V  | 
						
						
							| 39 | 
							
								1 2 12 13 36 38
							 | 
							bnj1015 | 
							⊢ ( ( 𝐺  ∈  𝐵  ∧  suc  𝑖  ∈  dom  𝐺 )  →  ( 𝐺 ‘ suc  𝑖 )  ⊆   trCl ( 𝑋 ,  𝐴 ,  𝑅 ) )  | 
						
						
							| 40 | 
							
								27 35 39
							 | 
							syl2anc | 
							⊢ ( ( 𝜃  ∧  𝜒  ∧  𝜂  ∧  ∃ 𝑝 𝜏 )  →  ( 𝐺 ‘ suc  𝑖 )  ⊆   trCl ( 𝑋 ,  𝐴 ,  𝑅 ) )  |