| Step | Hyp | Ref | Expression | 
						
							| 1 |  | oveq1 |  |-  ( x = xO -> ( x x.s 1s ) = ( xO x.s 1s ) ) | 
						
							| 2 |  | id |  |-  ( x = xO -> x = xO ) | 
						
							| 3 | 1 2 | eqeq12d |  |-  ( x = xO -> ( ( x x.s 1s ) = x <-> ( xO x.s 1s ) = xO ) ) | 
						
							| 4 |  | oveq1 |  |-  ( x = A -> ( x x.s 1s ) = ( A x.s 1s ) ) | 
						
							| 5 |  | id |  |-  ( x = A -> x = A ) | 
						
							| 6 | 4 5 | eqeq12d |  |-  ( x = A -> ( ( x x.s 1s ) = x <-> ( A x.s 1s ) = A ) ) | 
						
							| 7 |  | 1sno |  |-  1s e. No | 
						
							| 8 |  | mulsval |  |-  ( ( x e. No /\ 1s e. No ) -> ( x x.s 1s ) = ( ( { a | E. p e. ( _Left ` x ) E. q e. ( _Left ` 1s ) a = ( ( ( p x.s 1s ) +s ( x x.s q ) ) -s ( p x.s q ) ) } u. { b | E. r e. ( _Right ` x ) E. s e. ( _Right ` 1s ) b = ( ( ( r x.s 1s ) +s ( x x.s s ) ) -s ( r x.s s ) ) } ) |s ( { c | E. t e. ( _Left ` x ) E. u e. ( _Right ` 1s ) c = ( ( ( t x.s 1s ) +s ( x x.s u ) ) -s ( t x.s u ) ) } u. { d | E. v e. ( _Right ` x ) E. w e. ( _Left ` 1s ) d = ( ( ( v x.s 1s ) +s ( x x.s w ) ) -s ( v x.s w ) ) } ) ) ) | 
						
							| 9 | 7 8 | mpan2 |  |-  ( x e. No -> ( x x.s 1s ) = ( ( { a | E. p e. ( _Left ` x ) E. q e. ( _Left ` 1s ) a = ( ( ( p x.s 1s ) +s ( x x.s q ) ) -s ( p x.s q ) ) } u. { b | E. r e. ( _Right ` x ) E. s e. ( _Right ` 1s ) b = ( ( ( r x.s 1s ) +s ( x x.s s ) ) -s ( r x.s s ) ) } ) |s ( { c | E. t e. ( _Left ` x ) E. u e. ( _Right ` 1s ) c = ( ( ( t x.s 1s ) +s ( x x.s u ) ) -s ( t x.s u ) ) } u. { d | E. v e. ( _Right ` x ) E. w e. ( _Left ` 1s ) d = ( ( ( v x.s 1s ) +s ( x x.s w ) ) -s ( v x.s w ) ) } ) ) ) | 
						
							| 10 | 9 | adantr |  |-  ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( xO x.s 1s ) = xO ) -> ( x x.s 1s ) = ( ( { a | E. p e. ( _Left ` x ) E. q e. ( _Left ` 1s ) a = ( ( ( p x.s 1s ) +s ( x x.s q ) ) -s ( p x.s q ) ) } u. { b | E. r e. ( _Right ` x ) E. s e. ( _Right ` 1s ) b = ( ( ( r x.s 1s ) +s ( x x.s s ) ) -s ( r x.s s ) ) } ) |s ( { c | E. t e. ( _Left ` x ) E. u e. ( _Right ` 1s ) c = ( ( ( t x.s 1s ) +s ( x x.s u ) ) -s ( t x.s u ) ) } u. { d | E. v e. ( _Right ` x ) E. w e. ( _Left ` 1s ) d = ( ( ( v x.s 1s ) +s ( x x.s w ) ) -s ( v x.s w ) ) } ) ) ) | 
						
							| 11 |  | elun1 |  |-  ( p e. ( _Left ` x ) -> p e. ( ( _Left ` x ) u. ( _Right ` x ) ) ) | 
						
							| 12 |  | oveq1 |  |-  ( xO = p -> ( xO x.s 1s ) = ( p x.s 1s ) ) | 
						
							| 13 |  | id |  |-  ( xO = p -> xO = p ) | 
						
							| 14 | 12 13 | eqeq12d |  |-  ( xO = p -> ( ( xO x.s 1s ) = xO <-> ( p x.s 1s ) = p ) ) | 
						
							| 15 | 14 | rspcva |  |-  ( ( p e. ( ( _Left ` x ) u. ( _Right ` x ) ) /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( xO x.s 1s ) = xO ) -> ( p x.s 1s ) = p ) | 
						
							| 16 | 11 15 | sylan |  |-  ( ( p e. ( _Left ` x ) /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( xO x.s 1s ) = xO ) -> ( p x.s 1s ) = p ) | 
						
							| 17 | 16 | ancoms |  |-  ( ( A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( xO x.s 1s ) = xO /\ p e. ( _Left ` x ) ) -> ( p x.s 1s ) = p ) | 
						
							| 18 | 17 | adantll |  |-  ( ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( xO x.s 1s ) = xO ) /\ p e. ( _Left ` x ) ) -> ( p x.s 1s ) = p ) | 
						
							| 19 |  | muls01 |  |-  ( x e. No -> ( x x.s 0s ) = 0s ) | 
						
							| 20 | 19 | adantr |  |-  ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( xO x.s 1s ) = xO ) -> ( x x.s 0s ) = 0s ) | 
						
							| 21 | 20 | adantr |  |-  ( ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( xO x.s 1s ) = xO ) /\ p e. ( _Left ` x ) ) -> ( x x.s 0s ) = 0s ) | 
						
							| 22 | 18 21 | oveq12d |  |-  ( ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( xO x.s 1s ) = xO ) /\ p e. ( _Left ` x ) ) -> ( ( p x.s 1s ) +s ( x x.s 0s ) ) = ( p +s 0s ) ) | 
						
							| 23 |  | leftssno |  |-  ( _Left ` x ) C_ No | 
						
							| 24 | 23 | sseli |  |-  ( p e. ( _Left ` x ) -> p e. No ) | 
						
							| 25 | 24 | adantl |  |-  ( ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( xO x.s 1s ) = xO ) /\ p e. ( _Left ` x ) ) -> p e. No ) | 
						
							| 26 | 25 | addsridd |  |-  ( ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( xO x.s 1s ) = xO ) /\ p e. ( _Left ` x ) ) -> ( p +s 0s ) = p ) | 
						
							| 27 | 22 26 | eqtrd |  |-  ( ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( xO x.s 1s ) = xO ) /\ p e. ( _Left ` x ) ) -> ( ( p x.s 1s ) +s ( x x.s 0s ) ) = p ) | 
						
							| 28 |  | muls01 |  |-  ( p e. No -> ( p x.s 0s ) = 0s ) | 
						
							| 29 | 25 28 | syl |  |-  ( ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( xO x.s 1s ) = xO ) /\ p e. ( _Left ` x ) ) -> ( p x.s 0s ) = 0s ) | 
						
							| 30 | 27 29 | oveq12d |  |-  ( ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( xO x.s 1s ) = xO ) /\ p e. ( _Left ` x ) ) -> ( ( ( p x.s 1s ) +s ( x x.s 0s ) ) -s ( p x.s 0s ) ) = ( p -s 0s ) ) | 
						
							| 31 |  | subsid1 |  |-  ( p e. No -> ( p -s 0s ) = p ) | 
						
							| 32 | 25 31 | syl |  |-  ( ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( xO x.s 1s ) = xO ) /\ p e. ( _Left ` x ) ) -> ( p -s 0s ) = p ) | 
						
							| 33 | 30 32 | eqtrd |  |-  ( ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( xO x.s 1s ) = xO ) /\ p e. ( _Left ` x ) ) -> ( ( ( p x.s 1s ) +s ( x x.s 0s ) ) -s ( p x.s 0s ) ) = p ) | 
						
							| 34 | 33 | eqeq2d |  |-  ( ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( xO x.s 1s ) = xO ) /\ p e. ( _Left ` x ) ) -> ( a = ( ( ( p x.s 1s ) +s ( x x.s 0s ) ) -s ( p x.s 0s ) ) <-> a = p ) ) | 
						
							| 35 |  | equcom |  |-  ( a = p <-> p = a ) | 
						
							| 36 | 34 35 | bitrdi |  |-  ( ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( xO x.s 1s ) = xO ) /\ p e. ( _Left ` x ) ) -> ( a = ( ( ( p x.s 1s ) +s ( x x.s 0s ) ) -s ( p x.s 0s ) ) <-> p = a ) ) | 
						
							| 37 | 36 | rexbidva |  |-  ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( xO x.s 1s ) = xO ) -> ( E. p e. ( _Left ` x ) a = ( ( ( p x.s 1s ) +s ( x x.s 0s ) ) -s ( p x.s 0s ) ) <-> E. p e. ( _Left ` x ) p = a ) ) | 
						
							| 38 |  | left1s |  |-  ( _Left ` 1s ) = { 0s } | 
						
							| 39 | 38 | rexeqi |  |-  ( E. q e. ( _Left ` 1s ) a = ( ( ( p x.s 1s ) +s ( x x.s q ) ) -s ( p x.s q ) ) <-> E. q e. { 0s } a = ( ( ( p x.s 1s ) +s ( x x.s q ) ) -s ( p x.s q ) ) ) | 
						
							| 40 |  | 0sno |  |-  0s e. No | 
						
							| 41 | 40 | elexi |  |-  0s e. _V | 
						
							| 42 |  | oveq2 |  |-  ( q = 0s -> ( x x.s q ) = ( x x.s 0s ) ) | 
						
							| 43 | 42 | oveq2d |  |-  ( q = 0s -> ( ( p x.s 1s ) +s ( x x.s q ) ) = ( ( p x.s 1s ) +s ( x x.s 0s ) ) ) | 
						
							| 44 |  | oveq2 |  |-  ( q = 0s -> ( p x.s q ) = ( p x.s 0s ) ) | 
						
							| 45 | 43 44 | oveq12d |  |-  ( q = 0s -> ( ( ( p x.s 1s ) +s ( x x.s q ) ) -s ( p x.s q ) ) = ( ( ( p x.s 1s ) +s ( x x.s 0s ) ) -s ( p x.s 0s ) ) ) | 
						
							| 46 | 45 | eqeq2d |  |-  ( q = 0s -> ( a = ( ( ( p x.s 1s ) +s ( x x.s q ) ) -s ( p x.s q ) ) <-> a = ( ( ( p x.s 1s ) +s ( x x.s 0s ) ) -s ( p x.s 0s ) ) ) ) | 
						
							| 47 | 41 46 | rexsn |  |-  ( E. q e. { 0s } a = ( ( ( p x.s 1s ) +s ( x x.s q ) ) -s ( p x.s q ) ) <-> a = ( ( ( p x.s 1s ) +s ( x x.s 0s ) ) -s ( p x.s 0s ) ) ) | 
						
							| 48 | 39 47 | bitri |  |-  ( E. q e. ( _Left ` 1s ) a = ( ( ( p x.s 1s ) +s ( x x.s q ) ) -s ( p x.s q ) ) <-> a = ( ( ( p x.s 1s ) +s ( x x.s 0s ) ) -s ( p x.s 0s ) ) ) | 
						
							| 49 | 48 | rexbii |  |-  ( E. p e. ( _Left ` x ) E. q e. ( _Left ` 1s ) a = ( ( ( p x.s 1s ) +s ( x x.s q ) ) -s ( p x.s q ) ) <-> E. p e. ( _Left ` x ) a = ( ( ( p x.s 1s ) +s ( x x.s 0s ) ) -s ( p x.s 0s ) ) ) | 
						
							| 50 |  | risset |  |-  ( a e. ( _Left ` x ) <-> E. p e. ( _Left ` x ) p = a ) | 
						
							| 51 | 37 49 50 | 3bitr4g |  |-  ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( xO x.s 1s ) = xO ) -> ( E. p e. ( _Left ` x ) E. q e. ( _Left ` 1s ) a = ( ( ( p x.s 1s ) +s ( x x.s q ) ) -s ( p x.s q ) ) <-> a e. ( _Left ` x ) ) ) | 
						
							| 52 | 51 | eqabcdv |  |-  ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( xO x.s 1s ) = xO ) -> { a | E. p e. ( _Left ` x ) E. q e. ( _Left ` 1s ) a = ( ( ( p x.s 1s ) +s ( x x.s q ) ) -s ( p x.s q ) ) } = ( _Left ` x ) ) | 
						
							| 53 |  | rex0 |  |-  -. E. s e. (/) b = ( ( ( r x.s 1s ) +s ( x x.s s ) ) -s ( r x.s s ) ) | 
						
							| 54 |  | right1s |  |-  ( _Right ` 1s ) = (/) | 
						
							| 55 | 54 | rexeqi |  |-  ( E. s e. ( _Right ` 1s ) b = ( ( ( r x.s 1s ) +s ( x x.s s ) ) -s ( r x.s s ) ) <-> E. s e. (/) b = ( ( ( r x.s 1s ) +s ( x x.s s ) ) -s ( r x.s s ) ) ) | 
						
							| 56 | 53 55 | mtbir |  |-  -. E. s e. ( _Right ` 1s ) b = ( ( ( r x.s 1s ) +s ( x x.s s ) ) -s ( r x.s s ) ) | 
						
							| 57 | 56 | a1i |  |-  ( r e. ( _Right ` x ) -> -. E. s e. ( _Right ` 1s ) b = ( ( ( r x.s 1s ) +s ( x x.s s ) ) -s ( r x.s s ) ) ) | 
						
							| 58 | 57 | nrex |  |-  -. E. r e. ( _Right ` x ) E. s e. ( _Right ` 1s ) b = ( ( ( r x.s 1s ) +s ( x x.s s ) ) -s ( r x.s s ) ) | 
						
							| 59 | 58 | abf |  |-  { b | E. r e. ( _Right ` x ) E. s e. ( _Right ` 1s ) b = ( ( ( r x.s 1s ) +s ( x x.s s ) ) -s ( r x.s s ) ) } = (/) | 
						
							| 60 | 59 | a1i |  |-  ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( xO x.s 1s ) = xO ) -> { b | E. r e. ( _Right ` x ) E. s e. ( _Right ` 1s ) b = ( ( ( r x.s 1s ) +s ( x x.s s ) ) -s ( r x.s s ) ) } = (/) ) | 
						
							| 61 | 52 60 | uneq12d |  |-  ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( xO x.s 1s ) = xO ) -> ( { a | E. p e. ( _Left ` x ) E. q e. ( _Left ` 1s ) a = ( ( ( p x.s 1s ) +s ( x x.s q ) ) -s ( p x.s q ) ) } u. { b | E. r e. ( _Right ` x ) E. s e. ( _Right ` 1s ) b = ( ( ( r x.s 1s ) +s ( x x.s s ) ) -s ( r x.s s ) ) } ) = ( ( _Left ` x ) u. (/) ) ) | 
						
							| 62 |  | un0 |  |-  ( ( _Left ` x ) u. (/) ) = ( _Left ` x ) | 
						
							| 63 | 61 62 | eqtrdi |  |-  ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( xO x.s 1s ) = xO ) -> ( { a | E. p e. ( _Left ` x ) E. q e. ( _Left ` 1s ) a = ( ( ( p x.s 1s ) +s ( x x.s q ) ) -s ( p x.s q ) ) } u. { b | E. r e. ( _Right ` x ) E. s e. ( _Right ` 1s ) b = ( ( ( r x.s 1s ) +s ( x x.s s ) ) -s ( r x.s s ) ) } ) = ( _Left ` x ) ) | 
						
							| 64 |  | rex0 |  |-  -. E. u e. (/) c = ( ( ( t x.s 1s ) +s ( x x.s u ) ) -s ( t x.s u ) ) | 
						
							| 65 | 54 | rexeqi |  |-  ( E. u e. ( _Right ` 1s ) c = ( ( ( t x.s 1s ) +s ( x x.s u ) ) -s ( t x.s u ) ) <-> E. u e. (/) c = ( ( ( t x.s 1s ) +s ( x x.s u ) ) -s ( t x.s u ) ) ) | 
						
							| 66 | 64 65 | mtbir |  |-  -. E. u e. ( _Right ` 1s ) c = ( ( ( t x.s 1s ) +s ( x x.s u ) ) -s ( t x.s u ) ) | 
						
							| 67 | 66 | a1i |  |-  ( t e. ( _Left ` x ) -> -. E. u e. ( _Right ` 1s ) c = ( ( ( t x.s 1s ) +s ( x x.s u ) ) -s ( t x.s u ) ) ) | 
						
							| 68 | 67 | nrex |  |-  -. E. t e. ( _Left ` x ) E. u e. ( _Right ` 1s ) c = ( ( ( t x.s 1s ) +s ( x x.s u ) ) -s ( t x.s u ) ) | 
						
							| 69 | 68 | abf |  |-  { c | E. t e. ( _Left ` x ) E. u e. ( _Right ` 1s ) c = ( ( ( t x.s 1s ) +s ( x x.s u ) ) -s ( t x.s u ) ) } = (/) | 
						
							| 70 | 69 | a1i |  |-  ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( xO x.s 1s ) = xO ) -> { c | E. t e. ( _Left ` x ) E. u e. ( _Right ` 1s ) c = ( ( ( t x.s 1s ) +s ( x x.s u ) ) -s ( t x.s u ) ) } = (/) ) | 
						
							| 71 |  | elun2 |  |-  ( v e. ( _Right ` x ) -> v e. ( ( _Left ` x ) u. ( _Right ` x ) ) ) | 
						
							| 72 |  | oveq1 |  |-  ( xO = v -> ( xO x.s 1s ) = ( v x.s 1s ) ) | 
						
							| 73 |  | id |  |-  ( xO = v -> xO = v ) | 
						
							| 74 | 72 73 | eqeq12d |  |-  ( xO = v -> ( ( xO x.s 1s ) = xO <-> ( v x.s 1s ) = v ) ) | 
						
							| 75 | 74 | rspcva |  |-  ( ( v e. ( ( _Left ` x ) u. ( _Right ` x ) ) /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( xO x.s 1s ) = xO ) -> ( v x.s 1s ) = v ) | 
						
							| 76 | 71 75 | sylan |  |-  ( ( v e. ( _Right ` x ) /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( xO x.s 1s ) = xO ) -> ( v x.s 1s ) = v ) | 
						
							| 77 | 76 | ancoms |  |-  ( ( A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( xO x.s 1s ) = xO /\ v e. ( _Right ` x ) ) -> ( v x.s 1s ) = v ) | 
						
							| 78 | 77 | adantll |  |-  ( ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( xO x.s 1s ) = xO ) /\ v e. ( _Right ` x ) ) -> ( v x.s 1s ) = v ) | 
						
							| 79 | 20 | adantr |  |-  ( ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( xO x.s 1s ) = xO ) /\ v e. ( _Right ` x ) ) -> ( x x.s 0s ) = 0s ) | 
						
							| 80 | 78 79 | oveq12d |  |-  ( ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( xO x.s 1s ) = xO ) /\ v e. ( _Right ` x ) ) -> ( ( v x.s 1s ) +s ( x x.s 0s ) ) = ( v +s 0s ) ) | 
						
							| 81 |  | rightssno |  |-  ( _Right ` x ) C_ No | 
						
							| 82 | 81 | sseli |  |-  ( v e. ( _Right ` x ) -> v e. No ) | 
						
							| 83 | 82 | adantl |  |-  ( ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( xO x.s 1s ) = xO ) /\ v e. ( _Right ` x ) ) -> v e. No ) | 
						
							| 84 | 83 | addsridd |  |-  ( ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( xO x.s 1s ) = xO ) /\ v e. ( _Right ` x ) ) -> ( v +s 0s ) = v ) | 
						
							| 85 | 80 84 | eqtrd |  |-  ( ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( xO x.s 1s ) = xO ) /\ v e. ( _Right ` x ) ) -> ( ( v x.s 1s ) +s ( x x.s 0s ) ) = v ) | 
						
							| 86 |  | muls01 |  |-  ( v e. No -> ( v x.s 0s ) = 0s ) | 
						
							| 87 | 83 86 | syl |  |-  ( ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( xO x.s 1s ) = xO ) /\ v e. ( _Right ` x ) ) -> ( v x.s 0s ) = 0s ) | 
						
							| 88 | 85 87 | oveq12d |  |-  ( ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( xO x.s 1s ) = xO ) /\ v e. ( _Right ` x ) ) -> ( ( ( v x.s 1s ) +s ( x x.s 0s ) ) -s ( v x.s 0s ) ) = ( v -s 0s ) ) | 
						
							| 89 |  | subsid1 |  |-  ( v e. No -> ( v -s 0s ) = v ) | 
						
							| 90 | 83 89 | syl |  |-  ( ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( xO x.s 1s ) = xO ) /\ v e. ( _Right ` x ) ) -> ( v -s 0s ) = v ) | 
						
							| 91 | 88 90 | eqtrd |  |-  ( ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( xO x.s 1s ) = xO ) /\ v e. ( _Right ` x ) ) -> ( ( ( v x.s 1s ) +s ( x x.s 0s ) ) -s ( v x.s 0s ) ) = v ) | 
						
							| 92 | 91 | eqeq2d |  |-  ( ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( xO x.s 1s ) = xO ) /\ v e. ( _Right ` x ) ) -> ( d = ( ( ( v x.s 1s ) +s ( x x.s 0s ) ) -s ( v x.s 0s ) ) <-> d = v ) ) | 
						
							| 93 | 38 | rexeqi |  |-  ( E. w e. ( _Left ` 1s ) d = ( ( ( v x.s 1s ) +s ( x x.s w ) ) -s ( v x.s w ) ) <-> E. w e. { 0s } d = ( ( ( v x.s 1s ) +s ( x x.s w ) ) -s ( v x.s w ) ) ) | 
						
							| 94 |  | oveq2 |  |-  ( w = 0s -> ( x x.s w ) = ( x x.s 0s ) ) | 
						
							| 95 | 94 | oveq2d |  |-  ( w = 0s -> ( ( v x.s 1s ) +s ( x x.s w ) ) = ( ( v x.s 1s ) +s ( x x.s 0s ) ) ) | 
						
							| 96 |  | oveq2 |  |-  ( w = 0s -> ( v x.s w ) = ( v x.s 0s ) ) | 
						
							| 97 | 95 96 | oveq12d |  |-  ( w = 0s -> ( ( ( v x.s 1s ) +s ( x x.s w ) ) -s ( v x.s w ) ) = ( ( ( v x.s 1s ) +s ( x x.s 0s ) ) -s ( v x.s 0s ) ) ) | 
						
							| 98 | 97 | eqeq2d |  |-  ( w = 0s -> ( d = ( ( ( v x.s 1s ) +s ( x x.s w ) ) -s ( v x.s w ) ) <-> d = ( ( ( v x.s 1s ) +s ( x x.s 0s ) ) -s ( v x.s 0s ) ) ) ) | 
						
							| 99 | 41 98 | rexsn |  |-  ( E. w e. { 0s } d = ( ( ( v x.s 1s ) +s ( x x.s w ) ) -s ( v x.s w ) ) <-> d = ( ( ( v x.s 1s ) +s ( x x.s 0s ) ) -s ( v x.s 0s ) ) ) | 
						
							| 100 | 93 99 | bitri |  |-  ( E. w e. ( _Left ` 1s ) d = ( ( ( v x.s 1s ) +s ( x x.s w ) ) -s ( v x.s w ) ) <-> d = ( ( ( v x.s 1s ) +s ( x x.s 0s ) ) -s ( v x.s 0s ) ) ) | 
						
							| 101 |  | equcom |  |-  ( v = d <-> d = v ) | 
						
							| 102 | 92 100 101 | 3bitr4g |  |-  ( ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( xO x.s 1s ) = xO ) /\ v e. ( _Right ` x ) ) -> ( E. w e. ( _Left ` 1s ) d = ( ( ( v x.s 1s ) +s ( x x.s w ) ) -s ( v x.s w ) ) <-> v = d ) ) | 
						
							| 103 | 102 | rexbidva |  |-  ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( xO x.s 1s ) = xO ) -> ( E. v e. ( _Right ` x ) E. w e. ( _Left ` 1s ) d = ( ( ( v x.s 1s ) +s ( x x.s w ) ) -s ( v x.s w ) ) <-> E. v e. ( _Right ` x ) v = d ) ) | 
						
							| 104 |  | risset |  |-  ( d e. ( _Right ` x ) <-> E. v e. ( _Right ` x ) v = d ) | 
						
							| 105 | 103 104 | bitr4di |  |-  ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( xO x.s 1s ) = xO ) -> ( E. v e. ( _Right ` x ) E. w e. ( _Left ` 1s ) d = ( ( ( v x.s 1s ) +s ( x x.s w ) ) -s ( v x.s w ) ) <-> d e. ( _Right ` x ) ) ) | 
						
							| 106 | 105 | eqabcdv |  |-  ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( xO x.s 1s ) = xO ) -> { d | E. v e. ( _Right ` x ) E. w e. ( _Left ` 1s ) d = ( ( ( v x.s 1s ) +s ( x x.s w ) ) -s ( v x.s w ) ) } = ( _Right ` x ) ) | 
						
							| 107 | 70 106 | uneq12d |  |-  ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( xO x.s 1s ) = xO ) -> ( { c | E. t e. ( _Left ` x ) E. u e. ( _Right ` 1s ) c = ( ( ( t x.s 1s ) +s ( x x.s u ) ) -s ( t x.s u ) ) } u. { d | E. v e. ( _Right ` x ) E. w e. ( _Left ` 1s ) d = ( ( ( v x.s 1s ) +s ( x x.s w ) ) -s ( v x.s w ) ) } ) = ( (/) u. ( _Right ` x ) ) ) | 
						
							| 108 |  | 0un |  |-  ( (/) u. ( _Right ` x ) ) = ( _Right ` x ) | 
						
							| 109 | 107 108 | eqtrdi |  |-  ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( xO x.s 1s ) = xO ) -> ( { c | E. t e. ( _Left ` x ) E. u e. ( _Right ` 1s ) c = ( ( ( t x.s 1s ) +s ( x x.s u ) ) -s ( t x.s u ) ) } u. { d | E. v e. ( _Right ` x ) E. w e. ( _Left ` 1s ) d = ( ( ( v x.s 1s ) +s ( x x.s w ) ) -s ( v x.s w ) ) } ) = ( _Right ` x ) ) | 
						
							| 110 | 63 109 | oveq12d |  |-  ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( xO x.s 1s ) = xO ) -> ( ( { a | E. p e. ( _Left ` x ) E. q e. ( _Left ` 1s ) a = ( ( ( p x.s 1s ) +s ( x x.s q ) ) -s ( p x.s q ) ) } u. { b | E. r e. ( _Right ` x ) E. s e. ( _Right ` 1s ) b = ( ( ( r x.s 1s ) +s ( x x.s s ) ) -s ( r x.s s ) ) } ) |s ( { c | E. t e. ( _Left ` x ) E. u e. ( _Right ` 1s ) c = ( ( ( t x.s 1s ) +s ( x x.s u ) ) -s ( t x.s u ) ) } u. { d | E. v e. ( _Right ` x ) E. w e. ( _Left ` 1s ) d = ( ( ( v x.s 1s ) +s ( x x.s w ) ) -s ( v x.s w ) ) } ) ) = ( ( _Left ` x ) |s ( _Right ` x ) ) ) | 
						
							| 111 |  | lrcut |  |-  ( x e. No -> ( ( _Left ` x ) |s ( _Right ` x ) ) = x ) | 
						
							| 112 | 111 | adantr |  |-  ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( xO x.s 1s ) = xO ) -> ( ( _Left ` x ) |s ( _Right ` x ) ) = x ) | 
						
							| 113 | 10 110 112 | 3eqtrd |  |-  ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( xO x.s 1s ) = xO ) -> ( x x.s 1s ) = x ) | 
						
							| 114 | 113 | ex |  |-  ( x e. No -> ( A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( xO x.s 1s ) = xO -> ( x x.s 1s ) = x ) ) | 
						
							| 115 | 3 6 114 | noinds |  |-  ( A e. No -> ( A x.s 1s ) = A ) |