| Step | 
						Hyp | 
						Ref | 
						Expression | 
					
						
							| 1 | 
							
								
							 | 
							bnj1049.1 | 
							⊢ ( 𝜁  ↔  ( 𝑖  ∈  𝑛  ∧  𝑧  ∈  ( 𝑓 ‘ 𝑖 ) ) )  | 
						
						
							| 2 | 
							
								
							 | 
							bnj1049.2 | 
							⊢ ( 𝜂  ↔  ( ( 𝜃  ∧  𝜏  ∧  𝜒  ∧  𝜁 )  →  𝑧  ∈  𝐵 ) )  | 
						
						
							| 3 | 
							
								
							 | 
							df-ral | 
							⊢ ( ∀ 𝑖  ∈  𝑛 𝜂  ↔  ∀ 𝑖 ( 𝑖  ∈  𝑛  →  𝜂 ) )  | 
						
						
							| 4 | 
							
								2
							 | 
							imbi2i | 
							⊢ ( ( 𝑖  ∈  𝑛  →  𝜂 )  ↔  ( 𝑖  ∈  𝑛  →  ( ( 𝜃  ∧  𝜏  ∧  𝜒  ∧  𝜁 )  →  𝑧  ∈  𝐵 ) ) )  | 
						
						
							| 5 | 
							
								
							 | 
							impexp | 
							⊢ ( ( ( 𝑖  ∈  𝑛  ∧  ( 𝜃  ∧  𝜏  ∧  𝜒  ∧  𝜁 ) )  →  𝑧  ∈  𝐵 )  ↔  ( 𝑖  ∈  𝑛  →  ( ( 𝜃  ∧  𝜏  ∧  𝜒  ∧  𝜁 )  →  𝑧  ∈  𝐵 ) ) )  | 
						
						
							| 6 | 
							
								4 5
							 | 
							bitr4i | 
							⊢ ( ( 𝑖  ∈  𝑛  →  𝜂 )  ↔  ( ( 𝑖  ∈  𝑛  ∧  ( 𝜃  ∧  𝜏  ∧  𝜒  ∧  𝜁 ) )  →  𝑧  ∈  𝐵 ) )  | 
						
						
							| 7 | 
							
								1
							 | 
							simplbi | 
							⊢ ( 𝜁  →  𝑖  ∈  𝑛 )  | 
						
						
							| 8 | 
							
								7
							 | 
							bnj708 | 
							⊢ ( ( 𝜃  ∧  𝜏  ∧  𝜒  ∧  𝜁 )  →  𝑖  ∈  𝑛 )  | 
						
						
							| 9 | 
							
								8
							 | 
							pm4.71ri | 
							⊢ ( ( 𝜃  ∧  𝜏  ∧  𝜒  ∧  𝜁 )  ↔  ( 𝑖  ∈  𝑛  ∧  ( 𝜃  ∧  𝜏  ∧  𝜒  ∧  𝜁 ) ) )  | 
						
						
							| 10 | 
							
								9
							 | 
							bicomi | 
							⊢ ( ( 𝑖  ∈  𝑛  ∧  ( 𝜃  ∧  𝜏  ∧  𝜒  ∧  𝜁 ) )  ↔  ( 𝜃  ∧  𝜏  ∧  𝜒  ∧  𝜁 ) )  | 
						
						
							| 11 | 
							
								10
							 | 
							imbi1i | 
							⊢ ( ( ( 𝑖  ∈  𝑛  ∧  ( 𝜃  ∧  𝜏  ∧  𝜒  ∧  𝜁 ) )  →  𝑧  ∈  𝐵 )  ↔  ( ( 𝜃  ∧  𝜏  ∧  𝜒  ∧  𝜁 )  →  𝑧  ∈  𝐵 ) )  | 
						
						
							| 12 | 
							
								6 11
							 | 
							bitri | 
							⊢ ( ( 𝑖  ∈  𝑛  →  𝜂 )  ↔  ( ( 𝜃  ∧  𝜏  ∧  𝜒  ∧  𝜁 )  →  𝑧  ∈  𝐵 ) )  | 
						
						
							| 13 | 
							
								12 2
							 | 
							bitr4i | 
							⊢ ( ( 𝑖  ∈  𝑛  →  𝜂 )  ↔  𝜂 )  | 
						
						
							| 14 | 
							
								13
							 | 
							albii | 
							⊢ ( ∀ 𝑖 ( 𝑖  ∈  𝑛  →  𝜂 )  ↔  ∀ 𝑖 𝜂 )  | 
						
						
							| 15 | 
							
								3 14
							 | 
							bitri | 
							⊢ ( ∀ 𝑖  ∈  𝑛 𝜂  ↔  ∀ 𝑖 𝜂 )  |