| Step | 
						Hyp | 
						Ref | 
						Expression | 
					
						
							| 1 | 
							
								
							 | 
							bnj1040.1 | 
							 |-  ( ph' <-> [. j / i ]. ph )  | 
						
						
							| 2 | 
							
								
							 | 
							bnj1040.2 | 
							 |-  ( ps' <-> [. j / i ]. ps )  | 
						
						
							| 3 | 
							
								
							 | 
							bnj1040.3 | 
							 |-  ( ch <-> ( n e. D /\ f Fn n /\ ph /\ ps ) )  | 
						
						
							| 4 | 
							
								
							 | 
							bnj1040.4 | 
							 |-  ( ch' <-> [. j / i ]. ch )  | 
						
						
							| 5 | 
							
								3
							 | 
							sbcbii | 
							 |-  ( [. j / i ]. ch <-> [. j / i ]. ( n e. D /\ f Fn n /\ ph /\ ps ) )  | 
						
						
							| 6 | 
							
								
							 | 
							df-bnj17 | 
							 |-  ( ( [. j / i ]. n e. D /\ [. j / i ]. f Fn n /\ [. j / i ]. ph /\ [. j / i ]. ps ) <-> ( ( [. j / i ]. n e. D /\ [. j / i ]. f Fn n /\ [. j / i ]. ph ) /\ [. j / i ]. ps ) )  | 
						
						
							| 7 | 
							
								
							 | 
							vex | 
							 |-  j e. _V  | 
						
						
							| 8 | 
							
								7
							 | 
							bnj525 | 
							 |-  ( [. j / i ]. n e. D <-> n e. D )  | 
						
						
							| 9 | 
							
								8
							 | 
							bicomi | 
							 |-  ( n e. D <-> [. j / i ]. n e. D )  | 
						
						
							| 10 | 
							
								7
							 | 
							bnj525 | 
							 |-  ( [. j / i ]. f Fn n <-> f Fn n )  | 
						
						
							| 11 | 
							
								10
							 | 
							bicomi | 
							 |-  ( f Fn n <-> [. j / i ]. f Fn n )  | 
						
						
							| 12 | 
							
								9 11 1 2
							 | 
							bnj887 | 
							 |-  ( ( n e. D /\ f Fn n /\ ph' /\ ps' ) <-> ( [. j / i ]. n e. D /\ [. j / i ]. f Fn n /\ [. j / i ]. ph /\ [. j / i ]. ps ) )  | 
						
						
							| 13 | 
							
								
							 | 
							df-bnj17 | 
							 |-  ( ( n e. D /\ f Fn n /\ ph /\ ps ) <-> ( ( n e. D /\ f Fn n /\ ph ) /\ ps ) )  | 
						
						
							| 14 | 
							
								13
							 | 
							sbcbii | 
							 |-  ( [. j / i ]. ( n e. D /\ f Fn n /\ ph /\ ps ) <-> [. j / i ]. ( ( n e. D /\ f Fn n /\ ph ) /\ ps ) )  | 
						
						
							| 15 | 
							
								
							 | 
							sbcan | 
							 |-  ( [. j / i ]. ( ( n e. D /\ f Fn n /\ ph ) /\ ps ) <-> ( [. j / i ]. ( n e. D /\ f Fn n /\ ph ) /\ [. j / i ]. ps ) )  | 
						
						
							| 16 | 
							
								
							 | 
							sbc3an | 
							 |-  ( [. j / i ]. ( n e. D /\ f Fn n /\ ph ) <-> ( [. j / i ]. n e. D /\ [. j / i ]. f Fn n /\ [. j / i ]. ph ) )  | 
						
						
							| 17 | 
							
								16
							 | 
							anbi1i | 
							 |-  ( ( [. j / i ]. ( n e. D /\ f Fn n /\ ph ) /\ [. j / i ]. ps ) <-> ( ( [. j / i ]. n e. D /\ [. j / i ]. f Fn n /\ [. j / i ]. ph ) /\ [. j / i ]. ps ) )  | 
						
						
							| 18 | 
							
								14 15 17
							 | 
							3bitri | 
							 |-  ( [. j / i ]. ( n e. D /\ f Fn n /\ ph /\ ps ) <-> ( ( [. j / i ]. n e. D /\ [. j / i ]. f Fn n /\ [. j / i ]. ph ) /\ [. j / i ]. ps ) )  | 
						
						
							| 19 | 
							
								6 12 18
							 | 
							3bitr4ri | 
							 |-  ( [. j / i ]. ( n e. D /\ f Fn n /\ ph /\ ps ) <-> ( n e. D /\ f Fn n /\ ph' /\ ps' ) )  | 
						
						
							| 20 | 
							
								4 5 19
							 | 
							3bitri | 
							 |-  ( ch' <-> ( n e. D /\ f Fn n /\ ph' /\ ps' ) )  |