| Step | 
						Hyp | 
						Ref | 
						Expression | 
					
						
							| 1 | 
							
								
							 | 
							df-nr | 
							 |-  R. = ( ( P. X. P. ) /. ~R )  | 
						
						
							| 2 | 
							
								
							 | 
							breq1 | 
							 |-  ( [ <. x , y >. ] ~R = f -> ( [ <. x , y >. ] ~R . ] ~R <-> f . ] ~R ) )  | 
						
						
							| 3 | 
							
								
							 | 
							eqeq1 | 
							 |-  ( [ <. x , y >. ] ~R = f -> ( [ <. x , y >. ] ~R = [ <. z , w >. ] ~R <-> f = [ <. z , w >. ] ~R ) )  | 
						
						
							| 4 | 
							
								
							 | 
							breq2 | 
							 |-  ( [ <. x , y >. ] ~R = f -> ( [ <. z , w >. ] ~R . ] ~R <-> [ <. z , w >. ] ~R   | 
						
						
							| 5 | 
							
								3 4
							 | 
							orbi12d | 
							 |-  ( [ <. x , y >. ] ~R = f -> ( ( [ <. x , y >. ] ~R = [ <. z , w >. ] ~R \/ [ <. z , w >. ] ~R . ] ~R ) <-> ( f = [ <. z , w >. ] ~R \/ [ <. z , w >. ] ~R   | 
						
						
							| 6 | 
							
								5
							 | 
							notbid | 
							 |-  ( [ <. x , y >. ] ~R = f -> ( -. ( [ <. x , y >. ] ~R = [ <. z , w >. ] ~R \/ [ <. z , w >. ] ~R . ] ~R ) <-> -. ( f = [ <. z , w >. ] ~R \/ [ <. z , w >. ] ~R   | 
						
						
							| 7 | 
							
								2 6
							 | 
							bibi12d | 
							 |-  ( [ <. x , y >. ] ~R = f -> ( ( [ <. x , y >. ] ~R . ] ~R <-> -. ( [ <. x , y >. ] ~R = [ <. z , w >. ] ~R \/ [ <. z , w >. ] ~R . ] ~R ) ) <-> ( f . ] ~R <-> -. ( f = [ <. z , w >. ] ~R \/ [ <. z , w >. ] ~R   | 
						
						
							| 8 | 
							
								
							 | 
							breq2 | 
							 |-  ( [ <. z , w >. ] ~R = g -> ( f . ] ~R <-> f   | 
						
						
							| 9 | 
							
								
							 | 
							eqeq2 | 
							 |-  ( [ <. z , w >. ] ~R = g -> ( f = [ <. z , w >. ] ~R <-> f = g ) )  | 
						
						
							| 10 | 
							
								
							 | 
							breq1 | 
							 |-  ( [ <. z , w >. ] ~R = g -> ( [ <. z , w >. ] ~R  g   | 
						
						
							| 11 | 
							
								9 10
							 | 
							orbi12d | 
							 |-  ( [ <. z , w >. ] ~R = g -> ( ( f = [ <. z , w >. ] ~R \/ [ <. z , w >. ] ~R  ( f = g \/ g   | 
						
						
							| 12 | 
							
								11
							 | 
							notbid | 
							 |-  ( [ <. z , w >. ] ~R = g -> ( -. ( f = [ <. z , w >. ] ~R \/ [ <. z , w >. ] ~R  -. ( f = g \/ g   | 
						
						
							| 13 | 
							
								8 12
							 | 
							bibi12d | 
							 |-  ( [ <. z , w >. ] ~R = g -> ( ( f . ] ~R <-> -. ( f = [ <. z , w >. ] ~R \/ [ <. z , w >. ] ~R  ( f  -. ( f = g \/ g   | 
						
						
							| 14 | 
							
								
							 | 
							ltsrpr | 
							 |-  ( [ <. x , y >. ] ~R . ] ~R <-> ( x +P. w )   | 
						
						
							| 15 | 
							
								
							 | 
							addclpr | 
							 |-  ( ( x e. P. /\ w e. P. ) -> ( x +P. w ) e. P. )  | 
						
						
							| 16 | 
							
								
							 | 
							addclpr | 
							 |-  ( ( y e. P. /\ z e. P. ) -> ( y +P. z ) e. P. )  | 
						
						
							| 17 | 
							
								
							 | 
							ltsopr | 
							 |-    | 
						
						
							| 18 | 
							
								
							 | 
							sotric | 
							 |-  ( (  ( ( x +P. w )   -. ( ( x +P. w ) = ( y +P. z ) \/ ( y +P. z )    | 
						
						
							| 19 | 
							
								17 18
							 | 
							mpan | 
							 |-  ( ( ( x +P. w ) e. P. /\ ( y +P. z ) e. P. ) -> ( ( x +P. w )  -. ( ( x +P. w ) = ( y +P. z ) \/ ( y +P. z )    | 
						
						
							| 20 | 
							
								15 16 19
							 | 
							syl2an | 
							 |-  ( ( ( x e. P. /\ w e. P. ) /\ ( y e. P. /\ z e. P. ) ) -> ( ( x +P. w )  -. ( ( x +P. w ) = ( y +P. z ) \/ ( y +P. z )    | 
						
						
							| 21 | 
							
								20
							 | 
							an42s | 
							 |-  ( ( ( x e. P. /\ y e. P. ) /\ ( z e. P. /\ w e. P. ) ) -> ( ( x +P. w )  -. ( ( x +P. w ) = ( y +P. z ) \/ ( y +P. z )    | 
						
						
							| 22 | 
							
								
							 | 
							enreceq | 
							 |-  ( ( ( x e. P. /\ y e. P. ) /\ ( z e. P. /\ w e. P. ) ) -> ( [ <. x , y >. ] ~R = [ <. z , w >. ] ~R <-> ( x +P. w ) = ( y +P. z ) ) )  | 
						
						
							| 23 | 
							
								
							 | 
							ltsrpr | 
							 |-  ( [ <. z , w >. ] ~R . ] ~R <-> ( z +P. y )   | 
						
						
							| 24 | 
							
								
							 | 
							addcompr | 
							 |-  ( z +P. y ) = ( y +P. z )  | 
						
						
							| 25 | 
							
								
							 | 
							addcompr | 
							 |-  ( w +P. x ) = ( x +P. w )  | 
						
						
							| 26 | 
							
								24 25
							 | 
							breq12i | 
							 |-  ( ( z +P. y )  ( y +P. z )    | 
						
						
							| 27 | 
							
								23 26
							 | 
							bitri | 
							 |-  ( [ <. z , w >. ] ~R . ] ~R <-> ( y +P. z )   | 
						
						
							| 28 | 
							
								27
							 | 
							a1i | 
							 |-  ( ( ( x e. P. /\ y e. P. ) /\ ( z e. P. /\ w e. P. ) ) -> ( [ <. z , w >. ] ~R . ] ~R <-> ( y +P. z )   | 
						
						
							| 29 | 
							
								22 28
							 | 
							orbi12d | 
							 |-  ( ( ( x e. P. /\ y e. P. ) /\ ( z e. P. /\ w e. P. ) ) -> ( ( [ <. x , y >. ] ~R = [ <. z , w >. ] ~R \/ [ <. z , w >. ] ~R . ] ~R ) <-> ( ( x +P. w ) = ( y +P. z ) \/ ( y +P. z )   | 
						
						
							| 30 | 
							
								29
							 | 
							notbid | 
							 |-  ( ( ( x e. P. /\ y e. P. ) /\ ( z e. P. /\ w e. P. ) ) -> ( -. ( [ <. x , y >. ] ~R = [ <. z , w >. ] ~R \/ [ <. z , w >. ] ~R . ] ~R ) <-> -. ( ( x +P. w ) = ( y +P. z ) \/ ( y +P. z )   | 
						
						
							| 31 | 
							
								21 30
							 | 
							bitr4d | 
							 |-  ( ( ( x e. P. /\ y e. P. ) /\ ( z e. P. /\ w e. P. ) ) -> ( ( x +P. w )  -. ( [ <. x , y >. ] ~R = [ <. z , w >. ] ~R \/ [ <. z , w >. ] ~R . ] ~R ) ) )   | 
						
						
							| 32 | 
							
								14 31
							 | 
							bitrid | 
							 |-  ( ( ( x e. P. /\ y e. P. ) /\ ( z e. P. /\ w e. P. ) ) -> ( [ <. x , y >. ] ~R . ] ~R <-> -. ( [ <. x , y >. ] ~R = [ <. z , w >. ] ~R \/ [ <. z , w >. ] ~R . ] ~R ) ) )  | 
						
						
							| 33 | 
							
								1 7 13 32
							 | 
							2ecoptocl | 
							 |-  ( ( f e. R. /\ g e. R. ) -> ( f  -. ( f = g \/ g   | 
						
						
							| 34 | 
							
								2
							 | 
							anbi1d | 
							 |-  ( [ <. x , y >. ] ~R = f -> ( ( [ <. x , y >. ] ~R . ] ~R /\ [ <. z , w >. ] ~R . ] ~R ) <-> ( f . ] ~R /\ [ <. z , w >. ] ~R . ] ~R ) ) )  | 
						
						
							| 35 | 
							
								
							 | 
							breq1 | 
							 |-  ( [ <. x , y >. ] ~R = f -> ( [ <. x , y >. ] ~R . ] ~R <-> f . ] ~R ) )  | 
						
						
							| 36 | 
							
								34 35
							 | 
							imbi12d | 
							 |-  ( [ <. x , y >. ] ~R = f -> ( ( ( [ <. x , y >. ] ~R . ] ~R /\ [ <. z , w >. ] ~R . ] ~R ) -> [ <. x , y >. ] ~R . ] ~R ) <-> ( ( f . ] ~R /\ [ <. z , w >. ] ~R . ] ~R ) -> f . ] ~R ) ) )  | 
						
						
							| 37 | 
							
								
							 | 
							breq1 | 
							 |-  ( [ <. z , w >. ] ~R = g -> ( [ <. z , w >. ] ~R . ] ~R <-> g . ] ~R ) )  | 
						
						
							| 38 | 
							
								8 37
							 | 
							anbi12d | 
							 |-  ( [ <. z , w >. ] ~R = g -> ( ( f . ] ~R /\ [ <. z , w >. ] ~R . ] ~R ) <-> ( f . ] ~R ) ) )  | 
						
						
							| 39 | 
							
								38
							 | 
							imbi1d | 
							 |-  ( [ <. z , w >. ] ~R = g -> ( ( ( f . ] ~R /\ [ <. z , w >. ] ~R . ] ~R ) -> f . ] ~R ) <-> ( ( f . ] ~R ) -> f . ] ~R ) ) )  | 
						
						
							| 40 | 
							
								
							 | 
							breq2 | 
							 |-  ( [ <. v , u >. ] ~R = h -> ( g . ] ~R <-> g   | 
						
						
							| 41 | 
							
								40
							 | 
							anbi2d | 
							 |-  ( [ <. v , u >. ] ~R = h -> ( ( f . ] ~R ) <-> ( f   | 
						
						
							| 42 | 
							
								
							 | 
							breq2 | 
							 |-  ( [ <. v , u >. ] ~R = h -> ( f . ] ~R <-> f   | 
						
						
							| 43 | 
							
								41 42
							 | 
							imbi12d | 
							 |-  ( [ <. v , u >. ] ~R = h -> ( ( ( f . ] ~R ) -> f . ] ~R ) <-> ( ( f  f   | 
						
						
							| 44 | 
							
								
							 | 
							ovex | 
							 |-  ( x +P. w ) e. _V  | 
						
						
							| 45 | 
							
								
							 | 
							ovex | 
							 |-  ( y +P. z ) e. _V  | 
						
						
							| 46 | 
							
								
							 | 
							ltapr | 
							 |-  ( h e. P. -> ( f  ( h +P. f )    | 
						
						
							| 47 | 
							
								
							 | 
							vex | 
							 |-  u e. _V  | 
						
						
							| 48 | 
							
								
							 | 
							addcompr | 
							 |-  ( f +P. g ) = ( g +P. f )  | 
						
						
							| 49 | 
							
								44 45 46 47 48
							 | 
							caovord2 | 
							 |-  ( u e. P. -> ( ( x +P. w )  ( ( x +P. w ) +P. u )    | 
						
						
							| 50 | 
							
								
							 | 
							addasspr | 
							 |-  ( ( x +P. w ) +P. u ) = ( x +P. ( w +P. u ) )  | 
						
						
							| 51 | 
							
								
							 | 
							addasspr | 
							 |-  ( ( y +P. z ) +P. u ) = ( y +P. ( z +P. u ) )  | 
						
						
							| 52 | 
							
								50 51
							 | 
							breq12i | 
							 |-  ( ( ( x +P. w ) +P. u )  ( x +P. ( w +P. u ) )    | 
						
						
							| 53 | 
							
								49 52
							 | 
							bitrdi | 
							 |-  ( u e. P. -> ( ( x +P. w )  ( x +P. ( w +P. u ) )    | 
						
						
							| 54 | 
							
								14 53
							 | 
							bitrid | 
							 |-  ( u e. P. -> ( [ <. x , y >. ] ~R . ] ~R <-> ( x +P. ( w +P. u ) )   | 
						
						
							| 55 | 
							
								
							 | 
							ltsrpr | 
							 |-  ( [ <. z , w >. ] ~R . ] ~R <-> ( z +P. u )   | 
						
						
							| 56 | 
							
								
							 | 
							ltapr | 
							 |-  ( y e. P. -> ( ( z +P. u )  ( y +P. ( z +P. u ) )    | 
						
						
							| 57 | 
							
								55 56
							 | 
							bitrid | 
							 |-  ( y e. P. -> ( [ <. z , w >. ] ~R . ] ~R <-> ( y +P. ( z +P. u ) )   | 
						
						
							| 58 | 
							
								54 57
							 | 
							bi2anan9r | 
							 |-  ( ( y e. P. /\ u e. P. ) -> ( ( [ <. x , y >. ] ~R . ] ~R /\ [ <. z , w >. ] ~R . ] ~R ) <-> ( ( x +P. ( w +P. u ) )   | 
						
						
							| 59 | 
							
								
							 | 
							ltrelpr | 
							 |-    | 
						
						
							| 60 | 
							
								17 59
							 | 
							sotri | 
							 |-  ( ( ( x +P. ( w +P. u ) )  ( x +P. ( w +P. u ) )    | 
						
						
							| 61 | 
							
								
							 | 
							dmplp | 
							 |-  dom +P. = ( P. X. P. )  | 
						
						
							| 62 | 
							
								
							 | 
							0npr | 
							 |-  -. (/) e. P.  | 
						
						
							| 63 | 
							
								
							 | 
							ltapr | 
							 |-  ( w e. P. -> ( ( x +P. u )  ( w +P. ( x +P. u ) )    | 
						
						
							| 64 | 
							
								61 59 62 63
							 | 
							ndmovordi | 
							 |-  ( ( w +P. ( x +P. u ) )  ( x +P. u )    | 
						
						
							| 65 | 
							
								
							 | 
							vex | 
							 |-  x e. _V  | 
						
						
							| 66 | 
							
								
							 | 
							vex | 
							 |-  w e. _V  | 
						
						
							| 67 | 
							
								
							 | 
							addasspr | 
							 |-  ( ( f +P. g ) +P. h ) = ( f +P. ( g +P. h ) )  | 
						
						
							| 68 | 
							
								65 66 47 48 67
							 | 
							caov12 | 
							 |-  ( x +P. ( w +P. u ) ) = ( w +P. ( x +P. u ) )  | 
						
						
							| 69 | 
							
								
							 | 
							vex | 
							 |-  y e. _V  | 
						
						
							| 70 | 
							
								
							 | 
							vex | 
							 |-  v e. _V  | 
						
						
							| 71 | 
							
								69 66 70 48 67
							 | 
							caov12 | 
							 |-  ( y +P. ( w +P. v ) ) = ( w +P. ( y +P. v ) )  | 
						
						
							| 72 | 
							
								68 71
							 | 
							breq12i | 
							 |-  ( ( x +P. ( w +P. u ) )  ( w +P. ( x +P. u ) )    | 
						
						
							| 73 | 
							
								
							 | 
							ltsrpr | 
							 |-  ( [ <. x , y >. ] ~R . ] ~R <-> ( x +P. u )   | 
						
						
							| 74 | 
							
								64 72 73
							 | 
							3imtr4i | 
							 |-  ( ( x +P. ( w +P. u ) )  [ <. x , y >. ] ~R . ] ~R )   | 
						
						
							| 75 | 
							
								60 74
							 | 
							syl | 
							 |-  ( ( ( x +P. ( w +P. u ) )  [ <. x , y >. ] ~R . ] ~R )   | 
						
						
							| 76 | 
							
								58 75
							 | 
							biimtrdi | 
							 |-  ( ( y e. P. /\ u e. P. ) -> ( ( [ <. x , y >. ] ~R . ] ~R /\ [ <. z , w >. ] ~R . ] ~R ) -> [ <. x , y >. ] ~R . ] ~R ) )  | 
						
						
							| 77 | 
							
								76
							 | 
							ad2ant2l | 
							 |-  ( ( ( x e. P. /\ y e. P. ) /\ ( v e. P. /\ u e. P. ) ) -> ( ( [ <. x , y >. ] ~R . ] ~R /\ [ <. z , w >. ] ~R . ] ~R ) -> [ <. x , y >. ] ~R . ] ~R ) )  | 
						
						
							| 78 | 
							
								77
							 | 
							3adant2 | 
							 |-  ( ( ( x e. P. /\ y e. P. ) /\ ( z e. P. /\ w e. P. ) /\ ( v e. P. /\ u e. P. ) ) -> ( ( [ <. x , y >. ] ~R . ] ~R /\ [ <. z , w >. ] ~R . ] ~R ) -> [ <. x , y >. ] ~R . ] ~R ) )  | 
						
						
							| 79 | 
							
								1 36 39 43 78
							 | 
							3ecoptocl | 
							 |-  ( ( f e. R. /\ g e. R. /\ h e. R. ) -> ( ( f  f   | 
						
						
							| 80 | 
							
								33 79
							 | 
							isso2i | 
							 |-    |