| Step | 
						Hyp | 
						Ref | 
						Expression | 
					
						
							| 1 | 
							
								
							 | 
							bnj130.1 | 
							⊢ ( 𝜃  ↔  ( ( 𝑅  FrSe  𝐴  ∧  𝑥  ∈  𝐴 )  →  ∃! 𝑓 ( 𝑓  Fn  𝑛  ∧  𝜑  ∧  𝜓 ) ) )  | 
						
						
							| 2 | 
							
								
							 | 
							bnj130.2 | 
							⊢ ( 𝜑′  ↔  [ 1o  /  𝑛 ] 𝜑 )  | 
						
						
							| 3 | 
							
								
							 | 
							bnj130.3 | 
							⊢ ( 𝜓′  ↔  [ 1o  /  𝑛 ] 𝜓 )  | 
						
						
							| 4 | 
							
								
							 | 
							bnj130.4 | 
							⊢ ( 𝜃′  ↔  [ 1o  /  𝑛 ] 𝜃 )  | 
						
						
							| 5 | 
							
								1
							 | 
							sbcbii | 
							⊢ ( [ 1o  /  𝑛 ] 𝜃  ↔  [ 1o  /  𝑛 ] ( ( 𝑅  FrSe  𝐴  ∧  𝑥  ∈  𝐴 )  →  ∃! 𝑓 ( 𝑓  Fn  𝑛  ∧  𝜑  ∧  𝜓 ) ) )  | 
						
						
							| 6 | 
							
								
							 | 
							bnj105 | 
							⊢ 1o  ∈  V  | 
						
						
							| 7 | 
							
								6
							 | 
							bnj90 | 
							⊢ ( [ 1o  /  𝑛 ] 𝑓  Fn  𝑛  ↔  𝑓  Fn  1o )  | 
						
						
							| 8 | 
							
								7
							 | 
							bicomi | 
							⊢ ( 𝑓  Fn  1o  ↔  [ 1o  /  𝑛 ] 𝑓  Fn  𝑛 )  | 
						
						
							| 9 | 
							
								8 2 3
							 | 
							3anbi123i | 
							⊢ ( ( 𝑓  Fn  1o  ∧  𝜑′  ∧  𝜓′ )  ↔  ( [ 1o  /  𝑛 ] 𝑓  Fn  𝑛  ∧  [ 1o  /  𝑛 ] 𝜑  ∧  [ 1o  /  𝑛 ] 𝜓 ) )  | 
						
						
							| 10 | 
							
								
							 | 
							sbc3an | 
							⊢ ( [ 1o  /  𝑛 ] ( 𝑓  Fn  𝑛  ∧  𝜑  ∧  𝜓 )  ↔  ( [ 1o  /  𝑛 ] 𝑓  Fn  𝑛  ∧  [ 1o  /  𝑛 ] 𝜑  ∧  [ 1o  /  𝑛 ] 𝜓 ) )  | 
						
						
							| 11 | 
							
								9 10
							 | 
							bitr4i | 
							⊢ ( ( 𝑓  Fn  1o  ∧  𝜑′  ∧  𝜓′ )  ↔  [ 1o  /  𝑛 ] ( 𝑓  Fn  𝑛  ∧  𝜑  ∧  𝜓 ) )  | 
						
						
							| 12 | 
							
								11
							 | 
							eubii | 
							⊢ ( ∃! 𝑓 ( 𝑓  Fn  1o  ∧  𝜑′  ∧  𝜓′ )  ↔  ∃! 𝑓 [ 1o  /  𝑛 ] ( 𝑓  Fn  𝑛  ∧  𝜑  ∧  𝜓 ) )  | 
						
						
							| 13 | 
							
								6
							 | 
							bnj89 | 
							⊢ ( [ 1o  /  𝑛 ] ∃! 𝑓 ( 𝑓  Fn  𝑛  ∧  𝜑  ∧  𝜓 )  ↔  ∃! 𝑓 [ 1o  /  𝑛 ] ( 𝑓  Fn  𝑛  ∧  𝜑  ∧  𝜓 ) )  | 
						
						
							| 14 | 
							
								12 13
							 | 
							bitr4i | 
							⊢ ( ∃! 𝑓 ( 𝑓  Fn  1o  ∧  𝜑′  ∧  𝜓′ )  ↔  [ 1o  /  𝑛 ] ∃! 𝑓 ( 𝑓  Fn  𝑛  ∧  𝜑  ∧  𝜓 ) )  | 
						
						
							| 15 | 
							
								14
							 | 
							imbi2i | 
							⊢ ( ( ( 𝑅  FrSe  𝐴  ∧  𝑥  ∈  𝐴 )  →  ∃! 𝑓 ( 𝑓  Fn  1o  ∧  𝜑′  ∧  𝜓′ ) )  ↔  ( ( 𝑅  FrSe  𝐴  ∧  𝑥  ∈  𝐴 )  →  [ 1o  /  𝑛 ] ∃! 𝑓 ( 𝑓  Fn  𝑛  ∧  𝜑  ∧  𝜓 ) ) )  | 
						
						
							| 16 | 
							
								
							 | 
							nfv | 
							⊢ Ⅎ 𝑛 ( 𝑅  FrSe  𝐴  ∧  𝑥  ∈  𝐴 )  | 
						
						
							| 17 | 
							
								16
							 | 
							sbc19.21g | 
							⊢ ( 1o  ∈  V  →  ( [ 1o  /  𝑛 ] ( ( 𝑅  FrSe  𝐴  ∧  𝑥  ∈  𝐴 )  →  ∃! 𝑓 ( 𝑓  Fn  𝑛  ∧  𝜑  ∧  𝜓 ) )  ↔  ( ( 𝑅  FrSe  𝐴  ∧  𝑥  ∈  𝐴 )  →  [ 1o  /  𝑛 ] ∃! 𝑓 ( 𝑓  Fn  𝑛  ∧  𝜑  ∧  𝜓 ) ) ) )  | 
						
						
							| 18 | 
							
								6 17
							 | 
							ax-mp | 
							⊢ ( [ 1o  /  𝑛 ] ( ( 𝑅  FrSe  𝐴  ∧  𝑥  ∈  𝐴 )  →  ∃! 𝑓 ( 𝑓  Fn  𝑛  ∧  𝜑  ∧  𝜓 ) )  ↔  ( ( 𝑅  FrSe  𝐴  ∧  𝑥  ∈  𝐴 )  →  [ 1o  /  𝑛 ] ∃! 𝑓 ( 𝑓  Fn  𝑛  ∧  𝜑  ∧  𝜓 ) ) )  | 
						
						
							| 19 | 
							
								15 18
							 | 
							bitr4i | 
							⊢ ( ( ( 𝑅  FrSe  𝐴  ∧  𝑥  ∈  𝐴 )  →  ∃! 𝑓 ( 𝑓  Fn  1o  ∧  𝜑′  ∧  𝜓′ ) )  ↔  [ 1o  /  𝑛 ] ( ( 𝑅  FrSe  𝐴  ∧  𝑥  ∈  𝐴 )  →  ∃! 𝑓 ( 𝑓  Fn  𝑛  ∧  𝜑  ∧  𝜓 ) ) )  | 
						
						
							| 20 | 
							
								5 4 19
							 | 
							3bitr4i | 
							⊢ ( 𝜃′  ↔  ( ( 𝑅  FrSe  𝐴  ∧  𝑥  ∈  𝐴 )  →  ∃! 𝑓 ( 𝑓  Fn  1o  ∧  𝜑′  ∧  𝜓′ ) ) )  |