| Step | 
						Hyp | 
						Ref | 
						Expression | 
					
						
							| 1 | 
							
								
							 | 
							bnj976.1 | 
							 |-  ( ch <-> ( N e. D /\ f Fn N /\ ph /\ ps ) )  | 
						
						
							| 2 | 
							
								
							 | 
							bnj976.2 | 
							 |-  ( ph' <-> [. G / f ]. ph )  | 
						
						
							| 3 | 
							
								
							 | 
							bnj976.3 | 
							 |-  ( ps' <-> [. G / f ]. ps )  | 
						
						
							| 4 | 
							
								
							 | 
							bnj976.4 | 
							 |-  ( ch' <-> [. G / f ]. ch )  | 
						
						
							| 5 | 
							
								
							 | 
							bnj976.5 | 
							 |-  G e. _V  | 
						
						
							| 6 | 
							
								
							 | 
							sbccow | 
							 |-  ( [. G / h ]. [. h / f ]. ch <-> [. G / f ]. ch )  | 
						
						
							| 7 | 
							
								
							 | 
							bnj252 | 
							 |-  ( ( N e. D /\ f Fn N /\ ph /\ ps ) <-> ( N e. D /\ ( f Fn N /\ ph /\ ps ) ) )  | 
						
						
							| 8 | 
							
								7
							 | 
							sbcbii | 
							 |-  ( [. h / f ]. ( N e. D /\ f Fn N /\ ph /\ ps ) <-> [. h / f ]. ( N e. D /\ ( f Fn N /\ ph /\ ps ) ) )  | 
						
						
							| 9 | 
							
								1
							 | 
							sbcbii | 
							 |-  ( [. h / f ]. ch <-> [. h / f ]. ( N e. D /\ f Fn N /\ ph /\ ps ) )  | 
						
						
							| 10 | 
							
								
							 | 
							vex | 
							 |-  h e. _V  | 
						
						
							| 11 | 
							
								10
							 | 
							bnj525 | 
							 |-  ( [. h / f ]. N e. D <-> N e. D )  | 
						
						
							| 12 | 
							
								
							 | 
							sbc3an | 
							 |-  ( [. h / f ]. ( f Fn N /\ ph /\ ps ) <-> ( [. h / f ]. f Fn N /\ [. h / f ]. ph /\ [. h / f ]. ps ) )  | 
						
						
							| 13 | 
							
								
							 | 
							bnj62 | 
							 |-  ( [. h / f ]. f Fn N <-> h Fn N )  | 
						
						
							| 14 | 
							
								13
							 | 
							3anbi1i | 
							 |-  ( ( [. h / f ]. f Fn N /\ [. h / f ]. ph /\ [. h / f ]. ps ) <-> ( h Fn N /\ [. h / f ]. ph /\ [. h / f ]. ps ) )  | 
						
						
							| 15 | 
							
								12 14
							 | 
							bitri | 
							 |-  ( [. h / f ]. ( f Fn N /\ ph /\ ps ) <-> ( h Fn N /\ [. h / f ]. ph /\ [. h / f ]. ps ) )  | 
						
						
							| 16 | 
							
								11 15
							 | 
							anbi12i | 
							 |-  ( ( [. h / f ]. N e. D /\ [. h / f ]. ( f Fn N /\ ph /\ ps ) ) <-> ( N e. D /\ ( h Fn N /\ [. h / f ]. ph /\ [. h / f ]. ps ) ) )  | 
						
						
							| 17 | 
							
								
							 | 
							sbcan | 
							 |-  ( [. h / f ]. ( N e. D /\ ( f Fn N /\ ph /\ ps ) ) <-> ( [. h / f ]. N e. D /\ [. h / f ]. ( f Fn N /\ ph /\ ps ) ) )  | 
						
						
							| 18 | 
							
								
							 | 
							bnj252 | 
							 |-  ( ( N e. D /\ h Fn N /\ [. h / f ]. ph /\ [. h / f ]. ps ) <-> ( N e. D /\ ( h Fn N /\ [. h / f ]. ph /\ [. h / f ]. ps ) ) )  | 
						
						
							| 19 | 
							
								16 17 18
							 | 
							3bitr4ri | 
							 |-  ( ( N e. D /\ h Fn N /\ [. h / f ]. ph /\ [. h / f ]. ps ) <-> [. h / f ]. ( N e. D /\ ( f Fn N /\ ph /\ ps ) ) )  | 
						
						
							| 20 | 
							
								8 9 19
							 | 
							3bitr4i | 
							 |-  ( [. h / f ]. ch <-> ( N e. D /\ h Fn N /\ [. h / f ]. ph /\ [. h / f ]. ps ) )  | 
						
						
							| 21 | 
							
								
							 | 
							fneq1 | 
							 |-  ( h = G -> ( h Fn N <-> G Fn N ) )  | 
						
						
							| 22 | 
							
								
							 | 
							sbceq1a | 
							 |-  ( h = G -> ( [. h / f ]. ph <-> [. G / h ]. [. h / f ]. ph ) )  | 
						
						
							| 23 | 
							
								
							 | 
							sbccow | 
							 |-  ( [. G / h ]. [. h / f ]. ph <-> [. G / f ]. ph )  | 
						
						
							| 24 | 
							
								2 23
							 | 
							bitr4i | 
							 |-  ( ph' <-> [. G / h ]. [. h / f ]. ph )  | 
						
						
							| 25 | 
							
								22 24
							 | 
							bitr4di | 
							 |-  ( h = G -> ( [. h / f ]. ph <-> ph' ) )  | 
						
						
							| 26 | 
							
								
							 | 
							sbceq1a | 
							 |-  ( h = G -> ( [. h / f ]. ps <-> [. G / h ]. [. h / f ]. ps ) )  | 
						
						
							| 27 | 
							
								
							 | 
							sbccow | 
							 |-  ( [. G / h ]. [. h / f ]. ps <-> [. G / f ]. ps )  | 
						
						
							| 28 | 
							
								3 27
							 | 
							bitr4i | 
							 |-  ( ps' <-> [. G / h ]. [. h / f ]. ps )  | 
						
						
							| 29 | 
							
								26 28
							 | 
							bitr4di | 
							 |-  ( h = G -> ( [. h / f ]. ps <-> ps' ) )  | 
						
						
							| 30 | 
							
								21 25 29
							 | 
							3anbi123d | 
							 |-  ( h = G -> ( ( h Fn N /\ [. h / f ]. ph /\ [. h / f ]. ps ) <-> ( G Fn N /\ ph' /\ ps' ) ) )  | 
						
						
							| 31 | 
							
								30
							 | 
							anbi2d | 
							 |-  ( h = G -> ( ( N e. D /\ ( h Fn N /\ [. h / f ]. ph /\ [. h / f ]. ps ) ) <-> ( N e. D /\ ( G Fn N /\ ph' /\ ps' ) ) ) )  | 
						
						
							| 32 | 
							
								
							 | 
							bnj252 | 
							 |-  ( ( N e. D /\ G Fn N /\ ph' /\ ps' ) <-> ( N e. D /\ ( G Fn N /\ ph' /\ ps' ) ) )  | 
						
						
							| 33 | 
							
								31 18 32
							 | 
							3bitr4g | 
							 |-  ( h = G -> ( ( N e. D /\ h Fn N /\ [. h / f ]. ph /\ [. h / f ]. ps ) <-> ( N e. D /\ G Fn N /\ ph' /\ ps' ) ) )  | 
						
						
							| 34 | 
							
								20 33
							 | 
							bitrid | 
							 |-  ( h = G -> ( [. h / f ]. ch <-> ( N e. D /\ G Fn N /\ ph' /\ ps' ) ) )  | 
						
						
							| 35 | 
							
								5 34
							 | 
							sbcie | 
							 |-  ( [. G / h ]. [. h / f ]. ch <-> ( N e. D /\ G Fn N /\ ph' /\ ps' ) )  | 
						
						
							| 36 | 
							
								4 6 35
							 | 
							3bitr2i | 
							 |-  ( ch' <-> ( N e. D /\ G Fn N /\ ph' /\ ps' ) )  |