| Step | 
						Hyp | 
						Ref | 
						Expression | 
					
						
							| 1 | 
							
								
							 | 
							bnj969.1 | 
							⊢ ( 𝜑  ↔  ( 𝑓 ‘ ∅ )  =   pred ( 𝑋 ,  𝐴 ,  𝑅 ) )  | 
						
						
							| 2 | 
							
								
							 | 
							bnj969.2 | 
							⊢ ( 𝜓  ↔  ∀ 𝑖  ∈  ω ( suc  𝑖  ∈  𝑛  →  ( 𝑓 ‘ suc  𝑖 )  =  ∪  𝑦  ∈  ( 𝑓 ‘ 𝑖 )  pred ( 𝑦 ,  𝐴 ,  𝑅 ) ) )  | 
						
						
							| 3 | 
							
								
							 | 
							bnj969.3 | 
							⊢ ( 𝜒  ↔  ( 𝑛  ∈  𝐷  ∧  𝑓  Fn  𝑛  ∧  𝜑  ∧  𝜓 ) )  | 
						
						
							| 4 | 
							
								
							 | 
							bnj969.10 | 
							⊢ 𝐷  =  ( ω  ∖  { ∅ } )  | 
						
						
							| 5 | 
							
								
							 | 
							bnj969.12 | 
							⊢ 𝐶  =  ∪  𝑦  ∈  ( 𝑓 ‘ 𝑚 )  pred ( 𝑦 ,  𝐴 ,  𝑅 )  | 
						
						
							| 6 | 
							
								
							 | 
							bnj969.14 | 
							⊢ ( 𝜏  ↔  ( 𝑓  Fn  𝑛  ∧  𝜑  ∧  𝜓 ) )  | 
						
						
							| 7 | 
							
								
							 | 
							bnj969.15 | 
							⊢ ( 𝜎  ↔  ( 𝑛  ∈  𝐷  ∧  𝑝  =  suc  𝑛  ∧  𝑚  ∈  𝑛 ) )  | 
						
						
							| 8 | 
							
								
							 | 
							simpl | 
							⊢ ( ( ( 𝑅  FrSe  𝐴  ∧  𝑋  ∈  𝐴 )  ∧  ( 𝜒  ∧  𝑛  =  suc  𝑚  ∧  𝑝  =  suc  𝑛 ) )  →  ( 𝑅  FrSe  𝐴  ∧  𝑋  ∈  𝐴 ) )  | 
						
						
							| 9 | 
							
								
							 | 
							bnj667 | 
							⊢ ( ( 𝑛  ∈  𝐷  ∧  𝑓  Fn  𝑛  ∧  𝜑  ∧  𝜓 )  →  ( 𝑓  Fn  𝑛  ∧  𝜑  ∧  𝜓 ) )  | 
						
						
							| 10 | 
							
								9 3 6
							 | 
							3imtr4i | 
							⊢ ( 𝜒  →  𝜏 )  | 
						
						
							| 11 | 
							
								10
							 | 
							3ad2ant1 | 
							⊢ ( ( 𝜒  ∧  𝑛  =  suc  𝑚  ∧  𝑝  =  suc  𝑛 )  →  𝜏 )  | 
						
						
							| 12 | 
							
								11
							 | 
							adantl | 
							⊢ ( ( ( 𝑅  FrSe  𝐴  ∧  𝑋  ∈  𝐴 )  ∧  ( 𝜒  ∧  𝑛  =  suc  𝑚  ∧  𝑝  =  suc  𝑛 ) )  →  𝜏 )  | 
						
						
							| 13 | 
							
								3
							 | 
							bnj1232 | 
							⊢ ( 𝜒  →  𝑛  ∈  𝐷 )  | 
						
						
							| 14 | 
							
								
							 | 
							vex | 
							⊢ 𝑚  ∈  V  | 
						
						
							| 15 | 
							
								14
							 | 
							bnj216 | 
							⊢ ( 𝑛  =  suc  𝑚  →  𝑚  ∈  𝑛 )  | 
						
						
							| 16 | 
							
								
							 | 
							id | 
							⊢ ( 𝑝  =  suc  𝑛  →  𝑝  =  suc  𝑛 )  | 
						
						
							| 17 | 
							
								13 15 16
							 | 
							3anim123i | 
							⊢ ( ( 𝜒  ∧  𝑛  =  suc  𝑚  ∧  𝑝  =  suc  𝑛 )  →  ( 𝑛  ∈  𝐷  ∧  𝑚  ∈  𝑛  ∧  𝑝  =  suc  𝑛 ) )  | 
						
						
							| 18 | 
							
								
							 | 
							3ancomb | 
							⊢ ( ( 𝑛  ∈  𝐷  ∧  𝑝  =  suc  𝑛  ∧  𝑚  ∈  𝑛 )  ↔  ( 𝑛  ∈  𝐷  ∧  𝑚  ∈  𝑛  ∧  𝑝  =  suc  𝑛 ) )  | 
						
						
							| 19 | 
							
								7 18
							 | 
							bitri | 
							⊢ ( 𝜎  ↔  ( 𝑛  ∈  𝐷  ∧  𝑚  ∈  𝑛  ∧  𝑝  =  suc  𝑛 ) )  | 
						
						
							| 20 | 
							
								17 19
							 | 
							sylibr | 
							⊢ ( ( 𝜒  ∧  𝑛  =  suc  𝑚  ∧  𝑝  =  suc  𝑛 )  →  𝜎 )  | 
						
						
							| 21 | 
							
								20
							 | 
							adantl | 
							⊢ ( ( ( 𝑅  FrSe  𝐴  ∧  𝑋  ∈  𝐴 )  ∧  ( 𝜒  ∧  𝑛  =  suc  𝑚  ∧  𝑝  =  suc  𝑛 ) )  →  𝜎 )  | 
						
						
							| 22 | 
							
								8 12 21
							 | 
							jca32 | 
							⊢ ( ( ( 𝑅  FrSe  𝐴  ∧  𝑋  ∈  𝐴 )  ∧  ( 𝜒  ∧  𝑛  =  suc  𝑚  ∧  𝑝  =  suc  𝑛 ) )  →  ( ( 𝑅  FrSe  𝐴  ∧  𝑋  ∈  𝐴 )  ∧  ( 𝜏  ∧  𝜎 ) ) )  | 
						
						
							| 23 | 
							
								
							 | 
							bnj256 | 
							⊢ ( ( 𝑅  FrSe  𝐴  ∧  𝑋  ∈  𝐴  ∧  𝜏  ∧  𝜎 )  ↔  ( ( 𝑅  FrSe  𝐴  ∧  𝑋  ∈  𝐴 )  ∧  ( 𝜏  ∧  𝜎 ) ) )  | 
						
						
							| 24 | 
							
								22 23
							 | 
							sylibr | 
							⊢ ( ( ( 𝑅  FrSe  𝐴  ∧  𝑋  ∈  𝐴 )  ∧  ( 𝜒  ∧  𝑛  =  suc  𝑚  ∧  𝑝  =  suc  𝑛 ) )  →  ( 𝑅  FrSe  𝐴  ∧  𝑋  ∈  𝐴  ∧  𝜏  ∧  𝜎 ) )  | 
						
						
							| 25 | 
							
								4 6 7 1 2
							 | 
							bnj938 | 
							⊢ ( ( 𝑅  FrSe  𝐴  ∧  𝑋  ∈  𝐴  ∧  𝜏  ∧  𝜎 )  →  ∪  𝑦  ∈  ( 𝑓 ‘ 𝑚 )  pred ( 𝑦 ,  𝐴 ,  𝑅 )  ∈  V )  | 
						
						
							| 26 | 
							
								5 25
							 | 
							eqeltrid | 
							⊢ ( ( 𝑅  FrSe  𝐴  ∧  𝑋  ∈  𝐴  ∧  𝜏  ∧  𝜎 )  →  𝐶  ∈  V )  | 
						
						
							| 27 | 
							
								24 26
							 | 
							syl | 
							⊢ ( ( ( 𝑅  FrSe  𝐴  ∧  𝑋  ∈  𝐴 )  ∧  ( 𝜒  ∧  𝑛  =  suc  𝑚  ∧  𝑝  =  suc  𝑛 ) )  →  𝐶  ∈  V )  |