| Step | Hyp | Ref | Expression | 
						
							| 1 |  | precsexlem.1 |  |-  F = rec ( ( p e. _V |-> [_ ( 1st ` p ) / l ]_ [_ ( 2nd ` p ) / r ]_ <. ( l u. ( { a | E. xR e. ( _Right ` A ) E. yL e. l a = ( ( 1s +s ( ( xR -s A ) x.s yL ) ) /su xR ) } u. { a | E. xL e. { x e. ( _Left ` A ) | 0s . ) , <. { 0s } , (/) >. ) | 
						
							| 2 |  | fveq2 |  |-  ( p = q -> ( 1st ` p ) = ( 1st ` q ) ) | 
						
							| 3 |  | fveq2 |  |-  ( p = q -> ( 2nd ` p ) = ( 2nd ` q ) ) | 
						
							| 4 | 3 | csbeq1d |  |-  ( p = q -> [_ ( 2nd ` p ) / r ]_ <. ( l u. ( { a | E. xR e. ( _Right ` A ) E. yL e. l a = ( ( 1s +s ( ( xR -s A ) x.s yL ) ) /su xR ) } u. { a | E. xL e. { x e. ( _Left ` A ) | 0s . = [_ ( 2nd ` q ) / r ]_ <. ( l u. ( { a | E. xR e. ( _Right ` A ) E. yL e. l a = ( ( 1s +s ( ( xR -s A ) x.s yL ) ) /su xR ) } u. { a | E. xL e. { x e. ( _Left ` A ) | 0s . ) | 
						
							| 5 | 2 4 | csbeq12dv |  |-  ( p = q -> [_ ( 1st ` p ) / l ]_ [_ ( 2nd ` p ) / r ]_ <. ( l u. ( { a | E. xR e. ( _Right ` A ) E. yL e. l a = ( ( 1s +s ( ( xR -s A ) x.s yL ) ) /su xR ) } u. { a | E. xL e. { x e. ( _Left ` A ) | 0s . = [_ ( 1st ` q ) / l ]_ [_ ( 2nd ` q ) / r ]_ <. ( l u. ( { a | E. xR e. ( _Right ` A ) E. yL e. l a = ( ( 1s +s ( ( xR -s A ) x.s yL ) ) /su xR ) } u. { a | E. xL e. { x e. ( _Left ` A ) | 0s . ) | 
						
							| 6 |  | rexeq |  |-  ( r = s -> ( E. yR e. r a = ( ( 1s +s ( ( xL -s A ) x.s yR ) ) /su xL ) <-> E. yR e. s a = ( ( 1s +s ( ( xL -s A ) x.s yR ) ) /su xL ) ) ) | 
						
							| 7 | 6 | rexbidv |  |-  ( r = s -> ( E. xL e. { x e. ( _Left ` A ) | 0s  E. xL e. { x e. ( _Left ` A ) | 0s  | 
						
							| 8 | 7 | abbidv |  |-  ( r = s -> { a | E. xL e. { x e. ( _Left ` A ) | 0s  | 
						
							| 9 | 8 | uneq2d |  |-  ( r = s -> ( { a | E. xR e. ( _Right ` A ) E. yL e. l a = ( ( 1s +s ( ( xR -s A ) x.s yL ) ) /su xR ) } u. { a | E. xL e. { x e. ( _Left ` A ) | 0s  | 
						
							| 10 | 9 | uneq2d |  |-  ( r = s -> ( l u. ( { a | E. xR e. ( _Right ` A ) E. yL e. l a = ( ( 1s +s ( ( xR -s A ) x.s yL ) ) /su xR ) } u. { a | E. xL e. { x e. ( _Left ` A ) | 0s  | 
						
							| 11 |  | id |  |-  ( r = s -> r = s ) | 
						
							| 12 |  | rexeq |  |-  ( r = s -> ( E. yR e. r a = ( ( 1s +s ( ( xR -s A ) x.s yR ) ) /su xR ) <-> E. yR e. s a = ( ( 1s +s ( ( xR -s A ) x.s yR ) ) /su xR ) ) ) | 
						
							| 13 | 12 | rexbidv |  |-  ( r = s -> ( E. xR e. ( _Right ` A ) E. yR e. r a = ( ( 1s +s ( ( xR -s A ) x.s yR ) ) /su xR ) <-> E. xR e. ( _Right ` A ) E. yR e. s a = ( ( 1s +s ( ( xR -s A ) x.s yR ) ) /su xR ) ) ) | 
						
							| 14 | 13 | abbidv |  |-  ( r = s -> { a | E. xR e. ( _Right ` A ) E. yR e. r a = ( ( 1s +s ( ( xR -s A ) x.s yR ) ) /su xR ) } = { a | E. xR e. ( _Right ` A ) E. yR e. s a = ( ( 1s +s ( ( xR -s A ) x.s yR ) ) /su xR ) } ) | 
						
							| 15 | 14 | uneq2d |  |-  ( r = s -> ( { a | E. xL e. { x e. ( _Left ` A ) | 0s  | 
						
							| 16 | 11 15 | uneq12d |  |-  ( r = s -> ( r u. ( { a | E. xL e. { x e. ( _Left ` A ) | 0s  | 
						
							| 17 | 10 16 | opeq12d |  |-  ( r = s -> <. ( l u. ( { a | E. xR e. ( _Right ` A ) E. yL e. l a = ( ( 1s +s ( ( xR -s A ) x.s yL ) ) /su xR ) } u. { a | E. xL e. { x e. ( _Left ` A ) | 0s . = <. ( l u. ( { a | E. xR e. ( _Right ` A ) E. yL e. l a = ( ( 1s +s ( ( xR -s A ) x.s yL ) ) /su xR ) } u. { a | E. xL e. { x e. ( _Left ` A ) | 0s . ) | 
						
							| 18 |  | eqeq1 |  |-  ( a = b -> ( a = ( ( 1s +s ( ( xR -s A ) x.s yL ) ) /su xR ) <-> b = ( ( 1s +s ( ( xR -s A ) x.s yL ) ) /su xR ) ) ) | 
						
							| 19 | 18 | 2rexbidv |  |-  ( a = b -> ( E. xR e. ( _Right ` A ) E. yL e. l a = ( ( 1s +s ( ( xR -s A ) x.s yL ) ) /su xR ) <-> E. xR e. ( _Right ` A ) E. yL e. l b = ( ( 1s +s ( ( xR -s A ) x.s yL ) ) /su xR ) ) ) | 
						
							| 20 |  | oveq1 |  |-  ( xR = zR -> ( xR -s A ) = ( zR -s A ) ) | 
						
							| 21 | 20 | oveq1d |  |-  ( xR = zR -> ( ( xR -s A ) x.s yL ) = ( ( zR -s A ) x.s yL ) ) | 
						
							| 22 | 21 | oveq2d |  |-  ( xR = zR -> ( 1s +s ( ( xR -s A ) x.s yL ) ) = ( 1s +s ( ( zR -s A ) x.s yL ) ) ) | 
						
							| 23 |  | id |  |-  ( xR = zR -> xR = zR ) | 
						
							| 24 | 22 23 | oveq12d |  |-  ( xR = zR -> ( ( 1s +s ( ( xR -s A ) x.s yL ) ) /su xR ) = ( ( 1s +s ( ( zR -s A ) x.s yL ) ) /su zR ) ) | 
						
							| 25 | 24 | eqeq2d |  |-  ( xR = zR -> ( b = ( ( 1s +s ( ( xR -s A ) x.s yL ) ) /su xR ) <-> b = ( ( 1s +s ( ( zR -s A ) x.s yL ) ) /su zR ) ) ) | 
						
							| 26 |  | oveq2 |  |-  ( yL = w -> ( ( zR -s A ) x.s yL ) = ( ( zR -s A ) x.s w ) ) | 
						
							| 27 | 26 | oveq2d |  |-  ( yL = w -> ( 1s +s ( ( zR -s A ) x.s yL ) ) = ( 1s +s ( ( zR -s A ) x.s w ) ) ) | 
						
							| 28 | 27 | oveq1d |  |-  ( yL = w -> ( ( 1s +s ( ( zR -s A ) x.s yL ) ) /su zR ) = ( ( 1s +s ( ( zR -s A ) x.s w ) ) /su zR ) ) | 
						
							| 29 | 28 | eqeq2d |  |-  ( yL = w -> ( b = ( ( 1s +s ( ( zR -s A ) x.s yL ) ) /su zR ) <-> b = ( ( 1s +s ( ( zR -s A ) x.s w ) ) /su zR ) ) ) | 
						
							| 30 | 25 29 | cbvrex2vw |  |-  ( E. xR e. ( _Right ` A ) E. yL e. l b = ( ( 1s +s ( ( xR -s A ) x.s yL ) ) /su xR ) <-> E. zR e. ( _Right ` A ) E. w e. l b = ( ( 1s +s ( ( zR -s A ) x.s w ) ) /su zR ) ) | 
						
							| 31 | 19 30 | bitrdi |  |-  ( a = b -> ( E. xR e. ( _Right ` A ) E. yL e. l a = ( ( 1s +s ( ( xR -s A ) x.s yL ) ) /su xR ) <-> E. zR e. ( _Right ` A ) E. w e. l b = ( ( 1s +s ( ( zR -s A ) x.s w ) ) /su zR ) ) ) | 
						
							| 32 | 31 | cbvabv |  |-  { a | E. xR e. ( _Right ` A ) E. yL e. l a = ( ( 1s +s ( ( xR -s A ) x.s yL ) ) /su xR ) } = { b | E. zR e. ( _Right ` A ) E. w e. l b = ( ( 1s +s ( ( zR -s A ) x.s w ) ) /su zR ) } | 
						
							| 33 |  | eqeq1 |  |-  ( a = b -> ( a = ( ( 1s +s ( ( xL -s A ) x.s yR ) ) /su xL ) <-> b = ( ( 1s +s ( ( xL -s A ) x.s yR ) ) /su xL ) ) ) | 
						
							| 34 | 33 | 2rexbidv |  |-  ( a = b -> ( E. xL e. { x e. ( _Left ` A ) | 0s  E. xL e. { x e. ( _Left ` A ) | 0s  | 
						
							| 35 |  | oveq1 |  |-  ( xL = zL -> ( xL -s A ) = ( zL -s A ) ) | 
						
							| 36 | 35 | oveq1d |  |-  ( xL = zL -> ( ( xL -s A ) x.s yR ) = ( ( zL -s A ) x.s yR ) ) | 
						
							| 37 | 36 | oveq2d |  |-  ( xL = zL -> ( 1s +s ( ( xL -s A ) x.s yR ) ) = ( 1s +s ( ( zL -s A ) x.s yR ) ) ) | 
						
							| 38 |  | id |  |-  ( xL = zL -> xL = zL ) | 
						
							| 39 | 37 38 | oveq12d |  |-  ( xL = zL -> ( ( 1s +s ( ( xL -s A ) x.s yR ) ) /su xL ) = ( ( 1s +s ( ( zL -s A ) x.s yR ) ) /su zL ) ) | 
						
							| 40 | 39 | eqeq2d |  |-  ( xL = zL -> ( b = ( ( 1s +s ( ( xL -s A ) x.s yR ) ) /su xL ) <-> b = ( ( 1s +s ( ( zL -s A ) x.s yR ) ) /su zL ) ) ) | 
						
							| 41 |  | oveq2 |  |-  ( yR = t -> ( ( zL -s A ) x.s yR ) = ( ( zL -s A ) x.s t ) ) | 
						
							| 42 | 41 | oveq2d |  |-  ( yR = t -> ( 1s +s ( ( zL -s A ) x.s yR ) ) = ( 1s +s ( ( zL -s A ) x.s t ) ) ) | 
						
							| 43 | 42 | oveq1d |  |-  ( yR = t -> ( ( 1s +s ( ( zL -s A ) x.s yR ) ) /su zL ) = ( ( 1s +s ( ( zL -s A ) x.s t ) ) /su zL ) ) | 
						
							| 44 | 43 | eqeq2d |  |-  ( yR = t -> ( b = ( ( 1s +s ( ( zL -s A ) x.s yR ) ) /su zL ) <-> b = ( ( 1s +s ( ( zL -s A ) x.s t ) ) /su zL ) ) ) | 
						
							| 45 | 40 44 | cbvrex2vw |  |-  ( E. xL e. { x e. ( _Left ` A ) | 0s  E. zL e. { x e. ( _Left ` A ) | 0s  | 
						
							| 46 |  | breq2 |  |-  ( x = z -> ( 0s  0s  | 
						
							| 47 | 46 | cbvrabv |  |-  { x e. ( _Left ` A ) | 0s  | 
						
							| 48 | 47 | rexeqi |  |-  ( E. zL e. { x e. ( _Left ` A ) | 0s  E. zL e. { z e. ( _Left ` A ) | 0s  | 
						
							| 49 | 45 48 | bitri |  |-  ( E. xL e. { x e. ( _Left ` A ) | 0s  E. zL e. { z e. ( _Left ` A ) | 0s  | 
						
							| 50 | 34 49 | bitrdi |  |-  ( a = b -> ( E. xL e. { x e. ( _Left ` A ) | 0s  E. zL e. { z e. ( _Left ` A ) | 0s  | 
						
							| 51 | 50 | cbvabv |  |-  { a | E. xL e. { x e. ( _Left ` A ) | 0s  | 
						
							| 52 | 32 51 | uneq12i |  |-  ( { a | E. xR e. ( _Right ` A ) E. yL e. l a = ( ( 1s +s ( ( xR -s A ) x.s yL ) ) /su xR ) } u. { a | E. xL e. { x e. ( _Left ` A ) | 0s  | 
						
							| 53 | 52 | uneq2i |  |-  ( l u. ( { a | E. xR e. ( _Right ` A ) E. yL e. l a = ( ( 1s +s ( ( xR -s A ) x.s yL ) ) /su xR ) } u. { a | E. xL e. { x e. ( _Left ` A ) | 0s  | 
						
							| 54 |  | eqeq1 |  |-  ( a = b -> ( a = ( ( 1s +s ( ( xL -s A ) x.s yL ) ) /su xL ) <-> b = ( ( 1s +s ( ( xL -s A ) x.s yL ) ) /su xL ) ) ) | 
						
							| 55 | 54 | 2rexbidv |  |-  ( a = b -> ( E. xL e. { x e. ( _Left ` A ) | 0s  E. xL e. { x e. ( _Left ` A ) | 0s  | 
						
							| 56 | 35 | oveq1d |  |-  ( xL = zL -> ( ( xL -s A ) x.s yL ) = ( ( zL -s A ) x.s yL ) ) | 
						
							| 57 | 56 | oveq2d |  |-  ( xL = zL -> ( 1s +s ( ( xL -s A ) x.s yL ) ) = ( 1s +s ( ( zL -s A ) x.s yL ) ) ) | 
						
							| 58 | 57 38 | oveq12d |  |-  ( xL = zL -> ( ( 1s +s ( ( xL -s A ) x.s yL ) ) /su xL ) = ( ( 1s +s ( ( zL -s A ) x.s yL ) ) /su zL ) ) | 
						
							| 59 | 58 | eqeq2d |  |-  ( xL = zL -> ( b = ( ( 1s +s ( ( xL -s A ) x.s yL ) ) /su xL ) <-> b = ( ( 1s +s ( ( zL -s A ) x.s yL ) ) /su zL ) ) ) | 
						
							| 60 |  | oveq2 |  |-  ( yL = w -> ( ( zL -s A ) x.s yL ) = ( ( zL -s A ) x.s w ) ) | 
						
							| 61 | 60 | oveq2d |  |-  ( yL = w -> ( 1s +s ( ( zL -s A ) x.s yL ) ) = ( 1s +s ( ( zL -s A ) x.s w ) ) ) | 
						
							| 62 | 61 | oveq1d |  |-  ( yL = w -> ( ( 1s +s ( ( zL -s A ) x.s yL ) ) /su zL ) = ( ( 1s +s ( ( zL -s A ) x.s w ) ) /su zL ) ) | 
						
							| 63 | 62 | eqeq2d |  |-  ( yL = w -> ( b = ( ( 1s +s ( ( zL -s A ) x.s yL ) ) /su zL ) <-> b = ( ( 1s +s ( ( zL -s A ) x.s w ) ) /su zL ) ) ) | 
						
							| 64 | 59 63 | cbvrex2vw |  |-  ( E. xL e. { x e. ( _Left ` A ) | 0s  E. zL e. { x e. ( _Left ` A ) | 0s  | 
						
							| 65 | 47 | rexeqi |  |-  ( E. zL e. { x e. ( _Left ` A ) | 0s  E. zL e. { z e. ( _Left ` A ) | 0s  | 
						
							| 66 | 64 65 | bitri |  |-  ( E. xL e. { x e. ( _Left ` A ) | 0s  E. zL e. { z e. ( _Left ` A ) | 0s  | 
						
							| 67 | 55 66 | bitrdi |  |-  ( a = b -> ( E. xL e. { x e. ( _Left ` A ) | 0s  E. zL e. { z e. ( _Left ` A ) | 0s  | 
						
							| 68 | 67 | cbvabv |  |-  { a | E. xL e. { x e. ( _Left ` A ) | 0s  | 
						
							| 69 |  | eqeq1 |  |-  ( a = b -> ( a = ( ( 1s +s ( ( xR -s A ) x.s yR ) ) /su xR ) <-> b = ( ( 1s +s ( ( xR -s A ) x.s yR ) ) /su xR ) ) ) | 
						
							| 70 | 69 | 2rexbidv |  |-  ( a = b -> ( E. xR e. ( _Right ` A ) E. yR e. s a = ( ( 1s +s ( ( xR -s A ) x.s yR ) ) /su xR ) <-> E. xR e. ( _Right ` A ) E. yR e. s b = ( ( 1s +s ( ( xR -s A ) x.s yR ) ) /su xR ) ) ) | 
						
							| 71 | 20 | oveq1d |  |-  ( xR = zR -> ( ( xR -s A ) x.s yR ) = ( ( zR -s A ) x.s yR ) ) | 
						
							| 72 | 71 | oveq2d |  |-  ( xR = zR -> ( 1s +s ( ( xR -s A ) x.s yR ) ) = ( 1s +s ( ( zR -s A ) x.s yR ) ) ) | 
						
							| 73 | 72 23 | oveq12d |  |-  ( xR = zR -> ( ( 1s +s ( ( xR -s A ) x.s yR ) ) /su xR ) = ( ( 1s +s ( ( zR -s A ) x.s yR ) ) /su zR ) ) | 
						
							| 74 | 73 | eqeq2d |  |-  ( xR = zR -> ( b = ( ( 1s +s ( ( xR -s A ) x.s yR ) ) /su xR ) <-> b = ( ( 1s +s ( ( zR -s A ) x.s yR ) ) /su zR ) ) ) | 
						
							| 75 |  | oveq2 |  |-  ( yR = t -> ( ( zR -s A ) x.s yR ) = ( ( zR -s A ) x.s t ) ) | 
						
							| 76 | 75 | oveq2d |  |-  ( yR = t -> ( 1s +s ( ( zR -s A ) x.s yR ) ) = ( 1s +s ( ( zR -s A ) x.s t ) ) ) | 
						
							| 77 | 76 | oveq1d |  |-  ( yR = t -> ( ( 1s +s ( ( zR -s A ) x.s yR ) ) /su zR ) = ( ( 1s +s ( ( zR -s A ) x.s t ) ) /su zR ) ) | 
						
							| 78 | 77 | eqeq2d |  |-  ( yR = t -> ( b = ( ( 1s +s ( ( zR -s A ) x.s yR ) ) /su zR ) <-> b = ( ( 1s +s ( ( zR -s A ) x.s t ) ) /su zR ) ) ) | 
						
							| 79 | 74 78 | cbvrex2vw |  |-  ( E. xR e. ( _Right ` A ) E. yR e. s b = ( ( 1s +s ( ( xR -s A ) x.s yR ) ) /su xR ) <-> E. zR e. ( _Right ` A ) E. t e. s b = ( ( 1s +s ( ( zR -s A ) x.s t ) ) /su zR ) ) | 
						
							| 80 | 70 79 | bitrdi |  |-  ( a = b -> ( E. xR e. ( _Right ` A ) E. yR e. s a = ( ( 1s +s ( ( xR -s A ) x.s yR ) ) /su xR ) <-> E. zR e. ( _Right ` A ) E. t e. s b = ( ( 1s +s ( ( zR -s A ) x.s t ) ) /su zR ) ) ) | 
						
							| 81 | 80 | cbvabv |  |-  { a | E. xR e. ( _Right ` A ) E. yR e. s a = ( ( 1s +s ( ( xR -s A ) x.s yR ) ) /su xR ) } = { b | E. zR e. ( _Right ` A ) E. t e. s b = ( ( 1s +s ( ( zR -s A ) x.s t ) ) /su zR ) } | 
						
							| 82 | 68 81 | uneq12i |  |-  ( { a | E. xL e. { x e. ( _Left ` A ) | 0s  | 
						
							| 83 | 82 | uneq2i |  |-  ( s u. ( { a | E. xL e. { x e. ( _Left ` A ) | 0s  | 
						
							| 84 | 53 83 | opeq12i |  |-  <. ( l u. ( { a | E. xR e. ( _Right ` A ) E. yL e. l a = ( ( 1s +s ( ( xR -s A ) x.s yL ) ) /su xR ) } u. { a | E. xL e. { x e. ( _Left ` A ) | 0s . = <. ( l u. ( { b | E. zR e. ( _Right ` A ) E. w e. l b = ( ( 1s +s ( ( zR -s A ) x.s w ) ) /su zR ) } u. { b | E. zL e. { z e. ( _Left ` A ) | 0s . | 
						
							| 85 | 17 84 | eqtrdi |  |-  ( r = s -> <. ( l u. ( { a | E. xR e. ( _Right ` A ) E. yL e. l a = ( ( 1s +s ( ( xR -s A ) x.s yL ) ) /su xR ) } u. { a | E. xL e. { x e. ( _Left ` A ) | 0s . = <. ( l u. ( { b | E. zR e. ( _Right ` A ) E. w e. l b = ( ( 1s +s ( ( zR -s A ) x.s w ) ) /su zR ) } u. { b | E. zL e. { z e. ( _Left ` A ) | 0s . ) | 
						
							| 86 | 85 | cbvcsbv |  |-  [_ ( 2nd ` q ) / r ]_ <. ( l u. ( { a | E. xR e. ( _Right ` A ) E. yL e. l a = ( ( 1s +s ( ( xR -s A ) x.s yL ) ) /su xR ) } u. { a | E. xL e. { x e. ( _Left ` A ) | 0s . = [_ ( 2nd ` q ) / s ]_ <. ( l u. ( { b | E. zR e. ( _Right ` A ) E. w e. l b = ( ( 1s +s ( ( zR -s A ) x.s w ) ) /su zR ) } u. { b | E. zL e. { z e. ( _Left ` A ) | 0s . | 
						
							| 87 | 86 | csbeq2i |  |-  [_ ( 1st ` q ) / l ]_ [_ ( 2nd ` q ) / r ]_ <. ( l u. ( { a | E. xR e. ( _Right ` A ) E. yL e. l a = ( ( 1s +s ( ( xR -s A ) x.s yL ) ) /su xR ) } u. { a | E. xL e. { x e. ( _Left ` A ) | 0s . = [_ ( 1st ` q ) / l ]_ [_ ( 2nd ` q ) / s ]_ <. ( l u. ( { b | E. zR e. ( _Right ` A ) E. w e. l b = ( ( 1s +s ( ( zR -s A ) x.s w ) ) /su zR ) } u. { b | E. zL e. { z e. ( _Left ` A ) | 0s . | 
						
							| 88 |  | id |  |-  ( l = m -> l = m ) | 
						
							| 89 |  | rexeq |  |-  ( l = m -> ( E. w e. l b = ( ( 1s +s ( ( zR -s A ) x.s w ) ) /su zR ) <-> E. w e. m b = ( ( 1s +s ( ( zR -s A ) x.s w ) ) /su zR ) ) ) | 
						
							| 90 | 89 | rexbidv |  |-  ( l = m -> ( E. zR e. ( _Right ` A ) E. w e. l b = ( ( 1s +s ( ( zR -s A ) x.s w ) ) /su zR ) <-> E. zR e. ( _Right ` A ) E. w e. m b = ( ( 1s +s ( ( zR -s A ) x.s w ) ) /su zR ) ) ) | 
						
							| 91 | 90 | abbidv |  |-  ( l = m -> { b | E. zR e. ( _Right ` A ) E. w e. l b = ( ( 1s +s ( ( zR -s A ) x.s w ) ) /su zR ) } = { b | E. zR e. ( _Right ` A ) E. w e. m b = ( ( 1s +s ( ( zR -s A ) x.s w ) ) /su zR ) } ) | 
						
							| 92 | 91 | uneq1d |  |-  ( l = m -> ( { b | E. zR e. ( _Right ` A ) E. w e. l b = ( ( 1s +s ( ( zR -s A ) x.s w ) ) /su zR ) } u. { b | E. zL e. { z e. ( _Left ` A ) | 0s  | 
						
							| 93 | 88 92 | uneq12d |  |-  ( l = m -> ( l u. ( { b | E. zR e. ( _Right ` A ) E. w e. l b = ( ( 1s +s ( ( zR -s A ) x.s w ) ) /su zR ) } u. { b | E. zL e. { z e. ( _Left ` A ) | 0s  | 
						
							| 94 |  | rexeq |  |-  ( l = m -> ( E. w e. l b = ( ( 1s +s ( ( zL -s A ) x.s w ) ) /su zL ) <-> E. w e. m b = ( ( 1s +s ( ( zL -s A ) x.s w ) ) /su zL ) ) ) | 
						
							| 95 | 94 | rexbidv |  |-  ( l = m -> ( E. zL e. { z e. ( _Left ` A ) | 0s  E. zL e. { z e. ( _Left ` A ) | 0s  | 
						
							| 96 | 95 | abbidv |  |-  ( l = m -> { b | E. zL e. { z e. ( _Left ` A ) | 0s  | 
						
							| 97 | 96 | uneq1d |  |-  ( l = m -> ( { b | E. zL e. { z e. ( _Left ` A ) | 0s  | 
						
							| 98 | 97 | uneq2d |  |-  ( l = m -> ( s u. ( { b | E. zL e. { z e. ( _Left ` A ) | 0s  | 
						
							| 99 | 93 98 | opeq12d |  |-  ( l = m -> <. ( l u. ( { b | E. zR e. ( _Right ` A ) E. w e. l b = ( ( 1s +s ( ( zR -s A ) x.s w ) ) /su zR ) } u. { b | E. zL e. { z e. ( _Left ` A ) | 0s . = <. ( m u. ( { b | E. zR e. ( _Right ` A ) E. w e. m b = ( ( 1s +s ( ( zR -s A ) x.s w ) ) /su zR ) } u. { b | E. zL e. { z e. ( _Left ` A ) | 0s . ) | 
						
							| 100 | 99 | csbeq2dv |  |-  ( l = m -> [_ ( 2nd ` q ) / s ]_ <. ( l u. ( { b | E. zR e. ( _Right ` A ) E. w e. l b = ( ( 1s +s ( ( zR -s A ) x.s w ) ) /su zR ) } u. { b | E. zL e. { z e. ( _Left ` A ) | 0s . = [_ ( 2nd ` q ) / s ]_ <. ( m u. ( { b | E. zR e. ( _Right ` A ) E. w e. m b = ( ( 1s +s ( ( zR -s A ) x.s w ) ) /su zR ) } u. { b | E. zL e. { z e. ( _Left ` A ) | 0s . ) | 
						
							| 101 | 100 | cbvcsbv |  |-  [_ ( 1st ` q ) / l ]_ [_ ( 2nd ` q ) / s ]_ <. ( l u. ( { b | E. zR e. ( _Right ` A ) E. w e. l b = ( ( 1s +s ( ( zR -s A ) x.s w ) ) /su zR ) } u. { b | E. zL e. { z e. ( _Left ` A ) | 0s . = [_ ( 1st ` q ) / m ]_ [_ ( 2nd ` q ) / s ]_ <. ( m u. ( { b | E. zR e. ( _Right ` A ) E. w e. m b = ( ( 1s +s ( ( zR -s A ) x.s w ) ) /su zR ) } u. { b | E. zL e. { z e. ( _Left ` A ) | 0s . | 
						
							| 102 | 87 101 | eqtri |  |-  [_ ( 1st ` q ) / l ]_ [_ ( 2nd ` q ) / r ]_ <. ( l u. ( { a | E. xR e. ( _Right ` A ) E. yL e. l a = ( ( 1s +s ( ( xR -s A ) x.s yL ) ) /su xR ) } u. { a | E. xL e. { x e. ( _Left ` A ) | 0s . = [_ ( 1st ` q ) / m ]_ [_ ( 2nd ` q ) / s ]_ <. ( m u. ( { b | E. zR e. ( _Right ` A ) E. w e. m b = ( ( 1s +s ( ( zR -s A ) x.s w ) ) /su zR ) } u. { b | E. zL e. { z e. ( _Left ` A ) | 0s . | 
						
							| 103 | 5 102 | eqtrdi |  |-  ( p = q -> [_ ( 1st ` p ) / l ]_ [_ ( 2nd ` p ) / r ]_ <. ( l u. ( { a | E. xR e. ( _Right ` A ) E. yL e. l a = ( ( 1s +s ( ( xR -s A ) x.s yL ) ) /su xR ) } u. { a | E. xL e. { x e. ( _Left ` A ) | 0s . = [_ ( 1st ` q ) / m ]_ [_ ( 2nd ` q ) / s ]_ <. ( m u. ( { b | E. zR e. ( _Right ` A ) E. w e. m b = ( ( 1s +s ( ( zR -s A ) x.s w ) ) /su zR ) } u. { b | E. zL e. { z e. ( _Left ` A ) | 0s . ) | 
						
							| 104 | 103 | cbvmptv |  |-  ( p e. _V |-> [_ ( 1st ` p ) / l ]_ [_ ( 2nd ` p ) / r ]_ <. ( l u. ( { a | E. xR e. ( _Right ` A ) E. yL e. l a = ( ( 1s +s ( ( xR -s A ) x.s yL ) ) /su xR ) } u. { a | E. xL e. { x e. ( _Left ` A ) | 0s . ) = ( q e. _V |-> [_ ( 1st ` q ) / m ]_ [_ ( 2nd ` q ) / s ]_ <. ( m u. ( { b | E. zR e. ( _Right ` A ) E. w e. m b = ( ( 1s +s ( ( zR -s A ) x.s w ) ) /su zR ) } u. { b | E. zL e. { z e. ( _Left ` A ) | 0s . ) | 
						
							| 105 |  | rdgeq1 |  |-  ( ( p e. _V |-> [_ ( 1st ` p ) / l ]_ [_ ( 2nd ` p ) / r ]_ <. ( l u. ( { a | E. xR e. ( _Right ` A ) E. yL e. l a = ( ( 1s +s ( ( xR -s A ) x.s yL ) ) /su xR ) } u. { a | E. xL e. { x e. ( _Left ` A ) | 0s . ) = ( q e. _V |-> [_ ( 1st ` q ) / m ]_ [_ ( 2nd ` q ) / s ]_ <. ( m u. ( { b | E. zR e. ( _Right ` A ) E. w e. m b = ( ( 1s +s ( ( zR -s A ) x.s w ) ) /su zR ) } u. { b | E. zL e. { z e. ( _Left ` A ) | 0s . ) -> rec ( ( p e. _V |-> [_ ( 1st ` p ) / l ]_ [_ ( 2nd ` p ) / r ]_ <. ( l u. ( { a | E. xR e. ( _Right ` A ) E. yL e. l a = ( ( 1s +s ( ( xR -s A ) x.s yL ) ) /su xR ) } u. { a | E. xL e. { x e. ( _Left ` A ) | 0s . ) , <. { 0s } , (/) >. ) = rec ( ( q e. _V |-> [_ ( 1st ` q ) / m ]_ [_ ( 2nd ` q ) / s ]_ <. ( m u. ( { b | E. zR e. ( _Right ` A ) E. w e. m b = ( ( 1s +s ( ( zR -s A ) x.s w ) ) /su zR ) } u. { b | E. zL e. { z e. ( _Left ` A ) | 0s . ) , <. { 0s } , (/) >. ) ) | 
						
							| 106 | 104 105 | ax-mp |  |-  rec ( ( p e. _V |-> [_ ( 1st ` p ) / l ]_ [_ ( 2nd ` p ) / r ]_ <. ( l u. ( { a | E. xR e. ( _Right ` A ) E. yL e. l a = ( ( 1s +s ( ( xR -s A ) x.s yL ) ) /su xR ) } u. { a | E. xL e. { x e. ( _Left ` A ) | 0s . ) , <. { 0s } , (/) >. ) = rec ( ( q e. _V |-> [_ ( 1st ` q ) / m ]_ [_ ( 2nd ` q ) / s ]_ <. ( m u. ( { b | E. zR e. ( _Right ` A ) E. w e. m b = ( ( 1s +s ( ( zR -s A ) x.s w ) ) /su zR ) } u. { b | E. zL e. { z e. ( _Left ` A ) | 0s . ) , <. { 0s } , (/) >. ) | 
						
							| 107 | 1 106 | eqtri |  |-  F = rec ( ( q e. _V |-> [_ ( 1st ` q ) / m ]_ [_ ( 2nd ` q ) / s ]_ <. ( m u. ( { b | E. zR e. ( _Right ` A ) E. w e. m b = ( ( 1s +s ( ( zR -s A ) x.s w ) ) /su zR ) } u. { b | E. zL e. { z e. ( _Left ` A ) | 0s . ) , <. { 0s } , (/) >. ) |