| Step | 
						Hyp | 
						Ref | 
						Expression | 
					
						
							| 1 | 
							
								
							 | 
							bnj1021.1 | 
							⊢ ( 𝜑  ↔  ( 𝑓 ‘ ∅ )  =   pred ( 𝑋 ,  𝐴 ,  𝑅 ) )  | 
						
						
							| 2 | 
							
								
							 | 
							bnj1021.2 | 
							⊢ ( 𝜓  ↔  ∀ 𝑖  ∈  ω ( suc  𝑖  ∈  𝑛  →  ( 𝑓 ‘ suc  𝑖 )  =  ∪  𝑦  ∈  ( 𝑓 ‘ 𝑖 )  pred ( 𝑦 ,  𝐴 ,  𝑅 ) ) )  | 
						
						
							| 3 | 
							
								
							 | 
							bnj1021.3 | 
							⊢ ( 𝜒  ↔  ( 𝑛  ∈  𝐷  ∧  𝑓  Fn  𝑛  ∧  𝜑  ∧  𝜓 ) )  | 
						
						
							| 4 | 
							
								
							 | 
							bnj1021.4 | 
							⊢ ( 𝜃  ↔  ( 𝑅  FrSe  𝐴  ∧  𝑋  ∈  𝐴  ∧  𝑦  ∈   trCl ( 𝑋 ,  𝐴 ,  𝑅 )  ∧  𝑧  ∈   pred ( 𝑦 ,  𝐴 ,  𝑅 ) ) )  | 
						
						
							| 5 | 
							
								
							 | 
							bnj1021.5 | 
							⊢ ( 𝜏  ↔  ( 𝑚  ∈  ω  ∧  𝑛  =  suc  𝑚  ∧  𝑝  =  suc  𝑛 ) )  | 
						
						
							| 6 | 
							
								
							 | 
							bnj1021.6 | 
							⊢ ( 𝜂  ↔  ( 𝑖  ∈  𝑛  ∧  𝑦  ∈  ( 𝑓 ‘ 𝑖 ) ) )  | 
						
						
							| 7 | 
							
								
							 | 
							bnj1021.13 | 
							⊢ 𝐷  =  ( ω  ∖  { ∅ } )  | 
						
						
							| 8 | 
							
								
							 | 
							bnj1021.14 | 
							⊢ 𝐵  =  { 𝑓  ∣  ∃ 𝑛  ∈  𝐷 ( 𝑓  Fn  𝑛  ∧  𝜑  ∧  𝜓 ) }  | 
						
						
							| 9 | 
							
								1 2 3 4 5 6 7 8
							 | 
							bnj996 | 
							⊢ ∃ 𝑓 ∃ 𝑛 ∃ 𝑖 ∃ 𝑚 ∃ 𝑝 ( 𝜃  →  ( 𝜒  ∧  𝜏  ∧  𝜂 ) )  | 
						
						
							| 10 | 
							
								
							 | 
							anclb | 
							⊢ ( ( 𝜃  →  ( 𝜒  ∧  𝜏  ∧  𝜂 ) )  ↔  ( 𝜃  →  ( 𝜃  ∧  ( 𝜒  ∧  𝜏  ∧  𝜂 ) ) ) )  | 
						
						
							| 11 | 
							
								
							 | 
							bnj252 | 
							⊢ ( ( 𝜃  ∧  𝜒  ∧  𝜏  ∧  𝜂 )  ↔  ( 𝜃  ∧  ( 𝜒  ∧  𝜏  ∧  𝜂 ) ) )  | 
						
						
							| 12 | 
							
								11
							 | 
							imbi2i | 
							⊢ ( ( 𝜃  →  ( 𝜃  ∧  𝜒  ∧  𝜏  ∧  𝜂 ) )  ↔  ( 𝜃  →  ( 𝜃  ∧  ( 𝜒  ∧  𝜏  ∧  𝜂 ) ) ) )  | 
						
						
							| 13 | 
							
								10 12
							 | 
							bitr4i | 
							⊢ ( ( 𝜃  →  ( 𝜒  ∧  𝜏  ∧  𝜂 ) )  ↔  ( 𝜃  →  ( 𝜃  ∧  𝜒  ∧  𝜏  ∧  𝜂 ) ) )  | 
						
						
							| 14 | 
							
								13
							 | 
							2exbii | 
							⊢ ( ∃ 𝑚 ∃ 𝑝 ( 𝜃  →  ( 𝜒  ∧  𝜏  ∧  𝜂 ) )  ↔  ∃ 𝑚 ∃ 𝑝 ( 𝜃  →  ( 𝜃  ∧  𝜒  ∧  𝜏  ∧  𝜂 ) ) )  | 
						
						
							| 15 | 
							
								14
							 | 
							3exbii | 
							⊢ ( ∃ 𝑓 ∃ 𝑛 ∃ 𝑖 ∃ 𝑚 ∃ 𝑝 ( 𝜃  →  ( 𝜒  ∧  𝜏  ∧  𝜂 ) )  ↔  ∃ 𝑓 ∃ 𝑛 ∃ 𝑖 ∃ 𝑚 ∃ 𝑝 ( 𝜃  →  ( 𝜃  ∧  𝜒  ∧  𝜏  ∧  𝜂 ) ) )  | 
						
						
							| 16 | 
							
								9 15
							 | 
							mpbi | 
							⊢ ∃ 𝑓 ∃ 𝑛 ∃ 𝑖 ∃ 𝑚 ∃ 𝑝 ( 𝜃  →  ( 𝜃  ∧  𝜒  ∧  𝜏  ∧  𝜂 ) )  | 
						
						
							| 17 | 
							
								
							 | 
							19.37v | 
							⊢ ( ∃ 𝑝 ( 𝜃  →  ( 𝜃  ∧  𝜒  ∧  𝜏  ∧  𝜂 ) )  ↔  ( 𝜃  →  ∃ 𝑝 ( 𝜃  ∧  𝜒  ∧  𝜏  ∧  𝜂 ) ) )  | 
						
						
							| 18 | 
							
								
							 | 
							bnj1019 | 
							⊢ ( ∃ 𝑝 ( 𝜃  ∧  𝜒  ∧  𝜏  ∧  𝜂 )  ↔  ( 𝜃  ∧  𝜒  ∧  𝜂  ∧  ∃ 𝑝 𝜏 ) )  | 
						
						
							| 19 | 
							
								18
							 | 
							imbi2i | 
							⊢ ( ( 𝜃  →  ∃ 𝑝 ( 𝜃  ∧  𝜒  ∧  𝜏  ∧  𝜂 ) )  ↔  ( 𝜃  →  ( 𝜃  ∧  𝜒  ∧  𝜂  ∧  ∃ 𝑝 𝜏 ) ) )  | 
						
						
							| 20 | 
							
								17 19
							 | 
							bitri | 
							⊢ ( ∃ 𝑝 ( 𝜃  →  ( 𝜃  ∧  𝜒  ∧  𝜏  ∧  𝜂 ) )  ↔  ( 𝜃  →  ( 𝜃  ∧  𝜒  ∧  𝜂  ∧  ∃ 𝑝 𝜏 ) ) )  | 
						
						
							| 21 | 
							
								20
							 | 
							2exbii | 
							⊢ ( ∃ 𝑖 ∃ 𝑚 ∃ 𝑝 ( 𝜃  →  ( 𝜃  ∧  𝜒  ∧  𝜏  ∧  𝜂 ) )  ↔  ∃ 𝑖 ∃ 𝑚 ( 𝜃  →  ( 𝜃  ∧  𝜒  ∧  𝜂  ∧  ∃ 𝑝 𝜏 ) ) )  | 
						
						
							| 22 | 
							
								21
							 | 
							2exbii | 
							⊢ ( ∃ 𝑓 ∃ 𝑛 ∃ 𝑖 ∃ 𝑚 ∃ 𝑝 ( 𝜃  →  ( 𝜃  ∧  𝜒  ∧  𝜏  ∧  𝜂 ) )  ↔  ∃ 𝑓 ∃ 𝑛 ∃ 𝑖 ∃ 𝑚 ( 𝜃  →  ( 𝜃  ∧  𝜒  ∧  𝜂  ∧  ∃ 𝑝 𝜏 ) ) )  | 
						
						
							| 23 | 
							
								16 22
							 | 
							mpbi | 
							⊢ ∃ 𝑓 ∃ 𝑛 ∃ 𝑖 ∃ 𝑚 ( 𝜃  →  ( 𝜃  ∧  𝜒  ∧  𝜂  ∧  ∃ 𝑝 𝜏 ) )  |