| Step | Hyp | Ref | Expression | 
						
							| 1 |  | gsumval.b |  |-  B = ( Base ` G ) | 
						
							| 2 |  | gsumval.z |  |-  .0. = ( 0g ` G ) | 
						
							| 3 |  | gsumval.p |  |-  .+ = ( +g ` G ) | 
						
							| 4 |  | gsumval.o |  |-  O = { s e. B | A. t e. B ( ( s .+ t ) = t /\ ( t .+ s ) = t ) } | 
						
							| 5 |  | gsumval.w |  |-  ( ph -> W = ( `' F " ( _V \ O ) ) ) | 
						
							| 6 |  | gsumval.g |  |-  ( ph -> G e. V ) | 
						
							| 7 |  | gsumvalx.f |  |-  ( ph -> F e. X ) | 
						
							| 8 |  | gsumvalx.a |  |-  ( ph -> dom F = A ) | 
						
							| 9 |  | df-gsum |  |-  gsum = ( w e. _V , g e. _V |-> [_ { x e. ( Base ` w ) | A. y e. ( Base ` w ) ( ( x ( +g ` w ) y ) = y /\ ( y ( +g ` w ) x ) = y ) } / o ]_ if ( ran g C_ o , ( 0g ` w ) , if ( dom g e. ran ... , ( iota x E. m E. n e. ( ZZ>= ` m ) ( dom g = ( m ... n ) /\ x = ( seq m ( ( +g ` w ) , g ) ` n ) ) ) , ( iota x E. f [. ( `' g " ( _V \ o ) ) / y ]. ( f : ( 1 ... ( # ` y ) ) -1-1-onto-> y /\ x = ( seq 1 ( ( +g ` w ) , ( g o. f ) ) ` ( # ` y ) ) ) ) ) ) ) | 
						
							| 10 | 9 | a1i |  |-  ( ph -> gsum = ( w e. _V , g e. _V |-> [_ { x e. ( Base ` w ) | A. y e. ( Base ` w ) ( ( x ( +g ` w ) y ) = y /\ ( y ( +g ` w ) x ) = y ) } / o ]_ if ( ran g C_ o , ( 0g ` w ) , if ( dom g e. ran ... , ( iota x E. m E. n e. ( ZZ>= ` m ) ( dom g = ( m ... n ) /\ x = ( seq m ( ( +g ` w ) , g ) ` n ) ) ) , ( iota x E. f [. ( `' g " ( _V \ o ) ) / y ]. ( f : ( 1 ... ( # ` y ) ) -1-1-onto-> y /\ x = ( seq 1 ( ( +g ` w ) , ( g o. f ) ) ` ( # ` y ) ) ) ) ) ) ) ) | 
						
							| 11 |  | simprl |  |-  ( ( ph /\ ( w = G /\ g = F ) ) -> w = G ) | 
						
							| 12 | 11 | fveq2d |  |-  ( ( ph /\ ( w = G /\ g = F ) ) -> ( Base ` w ) = ( Base ` G ) ) | 
						
							| 13 | 12 1 | eqtr4di |  |-  ( ( ph /\ ( w = G /\ g = F ) ) -> ( Base ` w ) = B ) | 
						
							| 14 | 11 | fveq2d |  |-  ( ( ph /\ ( w = G /\ g = F ) ) -> ( +g ` w ) = ( +g ` G ) ) | 
						
							| 15 | 14 3 | eqtr4di |  |-  ( ( ph /\ ( w = G /\ g = F ) ) -> ( +g ` w ) = .+ ) | 
						
							| 16 | 15 | oveqd |  |-  ( ( ph /\ ( w = G /\ g = F ) ) -> ( x ( +g ` w ) y ) = ( x .+ y ) ) | 
						
							| 17 | 16 | eqeq1d |  |-  ( ( ph /\ ( w = G /\ g = F ) ) -> ( ( x ( +g ` w ) y ) = y <-> ( x .+ y ) = y ) ) | 
						
							| 18 | 15 | oveqd |  |-  ( ( ph /\ ( w = G /\ g = F ) ) -> ( y ( +g ` w ) x ) = ( y .+ x ) ) | 
						
							| 19 | 18 | eqeq1d |  |-  ( ( ph /\ ( w = G /\ g = F ) ) -> ( ( y ( +g ` w ) x ) = y <-> ( y .+ x ) = y ) ) | 
						
							| 20 | 17 19 | anbi12d |  |-  ( ( ph /\ ( w = G /\ g = F ) ) -> ( ( ( x ( +g ` w ) y ) = y /\ ( y ( +g ` w ) x ) = y ) <-> ( ( x .+ y ) = y /\ ( y .+ x ) = y ) ) ) | 
						
							| 21 | 13 20 | raleqbidv |  |-  ( ( ph /\ ( w = G /\ g = F ) ) -> ( A. y e. ( Base ` w ) ( ( x ( +g ` w ) y ) = y /\ ( y ( +g ` w ) x ) = y ) <-> A. y e. B ( ( x .+ y ) = y /\ ( y .+ x ) = y ) ) ) | 
						
							| 22 | 13 21 | rabeqbidv |  |-  ( ( ph /\ ( w = G /\ g = F ) ) -> { x e. ( Base ` w ) | A. y e. ( Base ` w ) ( ( x ( +g ` w ) y ) = y /\ ( y ( +g ` w ) x ) = y ) } = { x e. B | A. y e. B ( ( x .+ y ) = y /\ ( y .+ x ) = y ) } ) | 
						
							| 23 |  | oveq2 |  |-  ( t = y -> ( s .+ t ) = ( s .+ y ) ) | 
						
							| 24 |  | id |  |-  ( t = y -> t = y ) | 
						
							| 25 | 23 24 | eqeq12d |  |-  ( t = y -> ( ( s .+ t ) = t <-> ( s .+ y ) = y ) ) | 
						
							| 26 |  | oveq1 |  |-  ( t = y -> ( t .+ s ) = ( y .+ s ) ) | 
						
							| 27 | 26 24 | eqeq12d |  |-  ( t = y -> ( ( t .+ s ) = t <-> ( y .+ s ) = y ) ) | 
						
							| 28 | 25 27 | anbi12d |  |-  ( t = y -> ( ( ( s .+ t ) = t /\ ( t .+ s ) = t ) <-> ( ( s .+ y ) = y /\ ( y .+ s ) = y ) ) ) | 
						
							| 29 | 28 | cbvralvw |  |-  ( A. t e. B ( ( s .+ t ) = t /\ ( t .+ s ) = t ) <-> A. y e. B ( ( s .+ y ) = y /\ ( y .+ s ) = y ) ) | 
						
							| 30 |  | oveq1 |  |-  ( s = x -> ( s .+ y ) = ( x .+ y ) ) | 
						
							| 31 | 30 | eqeq1d |  |-  ( s = x -> ( ( s .+ y ) = y <-> ( x .+ y ) = y ) ) | 
						
							| 32 | 31 | ovanraleqv |  |-  ( s = x -> ( A. y e. B ( ( s .+ y ) = y /\ ( y .+ s ) = y ) <-> A. y e. B ( ( x .+ y ) = y /\ ( y .+ x ) = y ) ) ) | 
						
							| 33 | 29 32 | bitrid |  |-  ( s = x -> ( A. t e. B ( ( s .+ t ) = t /\ ( t .+ s ) = t ) <-> A. y e. B ( ( x .+ y ) = y /\ ( y .+ x ) = y ) ) ) | 
						
							| 34 | 33 | cbvrabv |  |-  { s e. B | A. t e. B ( ( s .+ t ) = t /\ ( t .+ s ) = t ) } = { x e. B | A. y e. B ( ( x .+ y ) = y /\ ( y .+ x ) = y ) } | 
						
							| 35 | 4 34 | eqtri |  |-  O = { x e. B | A. y e. B ( ( x .+ y ) = y /\ ( y .+ x ) = y ) } | 
						
							| 36 | 22 35 | eqtr4di |  |-  ( ( ph /\ ( w = G /\ g = F ) ) -> { x e. ( Base ` w ) | A. y e. ( Base ` w ) ( ( x ( +g ` w ) y ) = y /\ ( y ( +g ` w ) x ) = y ) } = O ) | 
						
							| 37 | 36 | csbeq1d |  |-  ( ( ph /\ ( w = G /\ g = F ) ) -> [_ { x e. ( Base ` w ) | A. y e. ( Base ` w ) ( ( x ( +g ` w ) y ) = y /\ ( y ( +g ` w ) x ) = y ) } / o ]_ if ( ran g C_ o , ( 0g ` w ) , if ( dom g e. ran ... , ( iota x E. m E. n e. ( ZZ>= ` m ) ( dom g = ( m ... n ) /\ x = ( seq m ( ( +g ` w ) , g ) ` n ) ) ) , ( iota x E. f [. ( `' g " ( _V \ o ) ) / y ]. ( f : ( 1 ... ( # ` y ) ) -1-1-onto-> y /\ x = ( seq 1 ( ( +g ` w ) , ( g o. f ) ) ` ( # ` y ) ) ) ) ) ) = [_ O / o ]_ if ( ran g C_ o , ( 0g ` w ) , if ( dom g e. ran ... , ( iota x E. m E. n e. ( ZZ>= ` m ) ( dom g = ( m ... n ) /\ x = ( seq m ( ( +g ` w ) , g ) ` n ) ) ) , ( iota x E. f [. ( `' g " ( _V \ o ) ) / y ]. ( f : ( 1 ... ( # ` y ) ) -1-1-onto-> y /\ x = ( seq 1 ( ( +g ` w ) , ( g o. f ) ) ` ( # ` y ) ) ) ) ) ) ) | 
						
							| 38 | 1 | fvexi |  |-  B e. _V | 
						
							| 39 | 4 38 | rabex2 |  |-  O e. _V | 
						
							| 40 | 39 | a1i |  |-  ( ( ph /\ ( w = G /\ g = F ) ) -> O e. _V ) | 
						
							| 41 |  | simplrr |  |-  ( ( ( ph /\ ( w = G /\ g = F ) ) /\ o = O ) -> g = F ) | 
						
							| 42 | 41 | rneqd |  |-  ( ( ( ph /\ ( w = G /\ g = F ) ) /\ o = O ) -> ran g = ran F ) | 
						
							| 43 |  | simpr |  |-  ( ( ( ph /\ ( w = G /\ g = F ) ) /\ o = O ) -> o = O ) | 
						
							| 44 | 42 43 | sseq12d |  |-  ( ( ( ph /\ ( w = G /\ g = F ) ) /\ o = O ) -> ( ran g C_ o <-> ran F C_ O ) ) | 
						
							| 45 | 11 | adantr |  |-  ( ( ( ph /\ ( w = G /\ g = F ) ) /\ o = O ) -> w = G ) | 
						
							| 46 | 45 | fveq2d |  |-  ( ( ( ph /\ ( w = G /\ g = F ) ) /\ o = O ) -> ( 0g ` w ) = ( 0g ` G ) ) | 
						
							| 47 | 46 2 | eqtr4di |  |-  ( ( ( ph /\ ( w = G /\ g = F ) ) /\ o = O ) -> ( 0g ` w ) = .0. ) | 
						
							| 48 | 41 | dmeqd |  |-  ( ( ( ph /\ ( w = G /\ g = F ) ) /\ o = O ) -> dom g = dom F ) | 
						
							| 49 | 8 | ad2antrr |  |-  ( ( ( ph /\ ( w = G /\ g = F ) ) /\ o = O ) -> dom F = A ) | 
						
							| 50 | 48 49 | eqtrd |  |-  ( ( ( ph /\ ( w = G /\ g = F ) ) /\ o = O ) -> dom g = A ) | 
						
							| 51 | 50 | eleq1d |  |-  ( ( ( ph /\ ( w = G /\ g = F ) ) /\ o = O ) -> ( dom g e. ran ... <-> A e. ran ... ) ) | 
						
							| 52 | 50 | eqeq1d |  |-  ( ( ( ph /\ ( w = G /\ g = F ) ) /\ o = O ) -> ( dom g = ( m ... n ) <-> A = ( m ... n ) ) ) | 
						
							| 53 | 15 | adantr |  |-  ( ( ( ph /\ ( w = G /\ g = F ) ) /\ o = O ) -> ( +g ` w ) = .+ ) | 
						
							| 54 | 53 | seqeq2d |  |-  ( ( ( ph /\ ( w = G /\ g = F ) ) /\ o = O ) -> seq m ( ( +g ` w ) , g ) = seq m ( .+ , g ) ) | 
						
							| 55 | 41 | seqeq3d |  |-  ( ( ( ph /\ ( w = G /\ g = F ) ) /\ o = O ) -> seq m ( .+ , g ) = seq m ( .+ , F ) ) | 
						
							| 56 | 54 55 | eqtrd |  |-  ( ( ( ph /\ ( w = G /\ g = F ) ) /\ o = O ) -> seq m ( ( +g ` w ) , g ) = seq m ( .+ , F ) ) | 
						
							| 57 | 56 | fveq1d |  |-  ( ( ( ph /\ ( w = G /\ g = F ) ) /\ o = O ) -> ( seq m ( ( +g ` w ) , g ) ` n ) = ( seq m ( .+ , F ) ` n ) ) | 
						
							| 58 | 57 | eqeq2d |  |-  ( ( ( ph /\ ( w = G /\ g = F ) ) /\ o = O ) -> ( x = ( seq m ( ( +g ` w ) , g ) ` n ) <-> x = ( seq m ( .+ , F ) ` n ) ) ) | 
						
							| 59 | 52 58 | anbi12d |  |-  ( ( ( ph /\ ( w = G /\ g = F ) ) /\ o = O ) -> ( ( dom g = ( m ... n ) /\ x = ( seq m ( ( +g ` w ) , g ) ` n ) ) <-> ( A = ( m ... n ) /\ x = ( seq m ( .+ , F ) ` n ) ) ) ) | 
						
							| 60 | 59 | rexbidv |  |-  ( ( ( ph /\ ( w = G /\ g = F ) ) /\ o = O ) -> ( E. n e. ( ZZ>= ` m ) ( dom g = ( m ... n ) /\ x = ( seq m ( ( +g ` w ) , g ) ` n ) ) <-> E. n e. ( ZZ>= ` m ) ( A = ( m ... n ) /\ x = ( seq m ( .+ , F ) ` n ) ) ) ) | 
						
							| 61 | 60 | exbidv |  |-  ( ( ( ph /\ ( w = G /\ g = F ) ) /\ o = O ) -> ( E. m E. n e. ( ZZ>= ` m ) ( dom g = ( m ... n ) /\ x = ( seq m ( ( +g ` w ) , g ) ` n ) ) <-> E. m E. n e. ( ZZ>= ` m ) ( A = ( m ... n ) /\ x = ( seq m ( .+ , F ) ` n ) ) ) ) | 
						
							| 62 | 61 | iotabidv |  |-  ( ( ( ph /\ ( w = G /\ g = F ) ) /\ o = O ) -> ( iota x E. m E. n e. ( ZZ>= ` m ) ( dom g = ( m ... n ) /\ x = ( seq m ( ( +g ` w ) , g ) ` n ) ) ) = ( iota x E. m E. n e. ( ZZ>= ` m ) ( A = ( m ... n ) /\ x = ( seq m ( .+ , F ) ` n ) ) ) ) | 
						
							| 63 | 43 | difeq2d |  |-  ( ( ( ph /\ ( w = G /\ g = F ) ) /\ o = O ) -> ( _V \ o ) = ( _V \ O ) ) | 
						
							| 64 | 63 | imaeq2d |  |-  ( ( ( ph /\ ( w = G /\ g = F ) ) /\ o = O ) -> ( `' F " ( _V \ o ) ) = ( `' F " ( _V \ O ) ) ) | 
						
							| 65 | 41 | cnveqd |  |-  ( ( ( ph /\ ( w = G /\ g = F ) ) /\ o = O ) -> `' g = `' F ) | 
						
							| 66 | 65 | imaeq1d |  |-  ( ( ( ph /\ ( w = G /\ g = F ) ) /\ o = O ) -> ( `' g " ( _V \ o ) ) = ( `' F " ( _V \ o ) ) ) | 
						
							| 67 | 5 | ad2antrr |  |-  ( ( ( ph /\ ( w = G /\ g = F ) ) /\ o = O ) -> W = ( `' F " ( _V \ O ) ) ) | 
						
							| 68 | 64 66 67 | 3eqtr4d |  |-  ( ( ( ph /\ ( w = G /\ g = F ) ) /\ o = O ) -> ( `' g " ( _V \ o ) ) = W ) | 
						
							| 69 | 68 | sbceq1d |  |-  ( ( ( ph /\ ( w = G /\ g = F ) ) /\ o = O ) -> ( [. ( `' g " ( _V \ o ) ) / y ]. ( f : ( 1 ... ( # ` y ) ) -1-1-onto-> y /\ x = ( seq 1 ( ( +g ` w ) , ( g o. f ) ) ` ( # ` y ) ) ) <-> [. W / y ]. ( f : ( 1 ... ( # ` y ) ) -1-1-onto-> y /\ x = ( seq 1 ( ( +g ` w ) , ( g o. f ) ) ` ( # ` y ) ) ) ) ) | 
						
							| 70 |  | cnvexg |  |-  ( F e. X -> `' F e. _V ) | 
						
							| 71 |  | imaexg |  |-  ( `' F e. _V -> ( `' F " ( _V \ O ) ) e. _V ) | 
						
							| 72 | 7 70 71 | 3syl |  |-  ( ph -> ( `' F " ( _V \ O ) ) e. _V ) | 
						
							| 73 | 5 72 | eqeltrd |  |-  ( ph -> W e. _V ) | 
						
							| 74 | 73 | ad2antrr |  |-  ( ( ( ph /\ ( w = G /\ g = F ) ) /\ o = O ) -> W e. _V ) | 
						
							| 75 |  | fveq2 |  |-  ( y = W -> ( # ` y ) = ( # ` W ) ) | 
						
							| 76 | 75 | adantl |  |-  ( ( ( ( ph /\ ( w = G /\ g = F ) ) /\ o = O ) /\ y = W ) -> ( # ` y ) = ( # ` W ) ) | 
						
							| 77 | 76 | oveq2d |  |-  ( ( ( ( ph /\ ( w = G /\ g = F ) ) /\ o = O ) /\ y = W ) -> ( 1 ... ( # ` y ) ) = ( 1 ... ( # ` W ) ) ) | 
						
							| 78 | 77 | f1oeq2d |  |-  ( ( ( ( ph /\ ( w = G /\ g = F ) ) /\ o = O ) /\ y = W ) -> ( f : ( 1 ... ( # ` y ) ) -1-1-onto-> y <-> f : ( 1 ... ( # ` W ) ) -1-1-onto-> y ) ) | 
						
							| 79 |  | f1oeq3 |  |-  ( y = W -> ( f : ( 1 ... ( # ` W ) ) -1-1-onto-> y <-> f : ( 1 ... ( # ` W ) ) -1-1-onto-> W ) ) | 
						
							| 80 | 79 | adantl |  |-  ( ( ( ( ph /\ ( w = G /\ g = F ) ) /\ o = O ) /\ y = W ) -> ( f : ( 1 ... ( # ` W ) ) -1-1-onto-> y <-> f : ( 1 ... ( # ` W ) ) -1-1-onto-> W ) ) | 
						
							| 81 | 78 80 | bitrd |  |-  ( ( ( ( ph /\ ( w = G /\ g = F ) ) /\ o = O ) /\ y = W ) -> ( f : ( 1 ... ( # ` y ) ) -1-1-onto-> y <-> f : ( 1 ... ( # ` W ) ) -1-1-onto-> W ) ) | 
						
							| 82 | 53 | seqeq2d |  |-  ( ( ( ph /\ ( w = G /\ g = F ) ) /\ o = O ) -> seq 1 ( ( +g ` w ) , ( g o. f ) ) = seq 1 ( .+ , ( g o. f ) ) ) | 
						
							| 83 | 41 | coeq1d |  |-  ( ( ( ph /\ ( w = G /\ g = F ) ) /\ o = O ) -> ( g o. f ) = ( F o. f ) ) | 
						
							| 84 | 83 | seqeq3d |  |-  ( ( ( ph /\ ( w = G /\ g = F ) ) /\ o = O ) -> seq 1 ( .+ , ( g o. f ) ) = seq 1 ( .+ , ( F o. f ) ) ) | 
						
							| 85 | 82 84 | eqtrd |  |-  ( ( ( ph /\ ( w = G /\ g = F ) ) /\ o = O ) -> seq 1 ( ( +g ` w ) , ( g o. f ) ) = seq 1 ( .+ , ( F o. f ) ) ) | 
						
							| 86 | 85 | adantr |  |-  ( ( ( ( ph /\ ( w = G /\ g = F ) ) /\ o = O ) /\ y = W ) -> seq 1 ( ( +g ` w ) , ( g o. f ) ) = seq 1 ( .+ , ( F o. f ) ) ) | 
						
							| 87 | 86 76 | fveq12d |  |-  ( ( ( ( ph /\ ( w = G /\ g = F ) ) /\ o = O ) /\ y = W ) -> ( seq 1 ( ( +g ` w ) , ( g o. f ) ) ` ( # ` y ) ) = ( seq 1 ( .+ , ( F o. f ) ) ` ( # ` W ) ) ) | 
						
							| 88 | 87 | eqeq2d |  |-  ( ( ( ( ph /\ ( w = G /\ g = F ) ) /\ o = O ) /\ y = W ) -> ( x = ( seq 1 ( ( +g ` w ) , ( g o. f ) ) ` ( # ` y ) ) <-> x = ( seq 1 ( .+ , ( F o. f ) ) ` ( # ` W ) ) ) ) | 
						
							| 89 | 81 88 | anbi12d |  |-  ( ( ( ( ph /\ ( w = G /\ g = F ) ) /\ o = O ) /\ y = W ) -> ( ( f : ( 1 ... ( # ` y ) ) -1-1-onto-> y /\ x = ( seq 1 ( ( +g ` w ) , ( g o. f ) ) ` ( # ` y ) ) ) <-> ( f : ( 1 ... ( # ` W ) ) -1-1-onto-> W /\ x = ( seq 1 ( .+ , ( F o. f ) ) ` ( # ` W ) ) ) ) ) | 
						
							| 90 | 74 89 | sbcied |  |-  ( ( ( ph /\ ( w = G /\ g = F ) ) /\ o = O ) -> ( [. W / y ]. ( f : ( 1 ... ( # ` y ) ) -1-1-onto-> y /\ x = ( seq 1 ( ( +g ` w ) , ( g o. f ) ) ` ( # ` y ) ) ) <-> ( f : ( 1 ... ( # ` W ) ) -1-1-onto-> W /\ x = ( seq 1 ( .+ , ( F o. f ) ) ` ( # ` W ) ) ) ) ) | 
						
							| 91 | 69 90 | bitrd |  |-  ( ( ( ph /\ ( w = G /\ g = F ) ) /\ o = O ) -> ( [. ( `' g " ( _V \ o ) ) / y ]. ( f : ( 1 ... ( # ` y ) ) -1-1-onto-> y /\ x = ( seq 1 ( ( +g ` w ) , ( g o. f ) ) ` ( # ` y ) ) ) <-> ( f : ( 1 ... ( # ` W ) ) -1-1-onto-> W /\ x = ( seq 1 ( .+ , ( F o. f ) ) ` ( # ` W ) ) ) ) ) | 
						
							| 92 | 91 | exbidv |  |-  ( ( ( ph /\ ( w = G /\ g = F ) ) /\ o = O ) -> ( E. f [. ( `' g " ( _V \ o ) ) / y ]. ( f : ( 1 ... ( # ` y ) ) -1-1-onto-> y /\ x = ( seq 1 ( ( +g ` w ) , ( g o. f ) ) ` ( # ` y ) ) ) <-> E. f ( f : ( 1 ... ( # ` W ) ) -1-1-onto-> W /\ x = ( seq 1 ( .+ , ( F o. f ) ) ` ( # ` W ) ) ) ) ) | 
						
							| 93 | 92 | iotabidv |  |-  ( ( ( ph /\ ( w = G /\ g = F ) ) /\ o = O ) -> ( iota x E. f [. ( `' g " ( _V \ o ) ) / y ]. ( f : ( 1 ... ( # ` y ) ) -1-1-onto-> y /\ x = ( seq 1 ( ( +g ` w ) , ( g o. f ) ) ` ( # ` y ) ) ) ) = ( iota x E. f ( f : ( 1 ... ( # ` W ) ) -1-1-onto-> W /\ x = ( seq 1 ( .+ , ( F o. f ) ) ` ( # ` W ) ) ) ) ) | 
						
							| 94 | 51 62 93 | ifbieq12d |  |-  ( ( ( ph /\ ( w = G /\ g = F ) ) /\ o = O ) -> if ( dom g e. ran ... , ( iota x E. m E. n e. ( ZZ>= ` m ) ( dom g = ( m ... n ) /\ x = ( seq m ( ( +g ` w ) , g ) ` n ) ) ) , ( iota x E. f [. ( `' g " ( _V \ o ) ) / y ]. ( f : ( 1 ... ( # ` y ) ) -1-1-onto-> y /\ x = ( seq 1 ( ( +g ` w ) , ( g o. f ) ) ` ( # ` y ) ) ) ) ) = if ( A e. ran ... , ( iota x E. m E. n e. ( ZZ>= ` m ) ( A = ( m ... n ) /\ x = ( seq m ( .+ , F ) ` n ) ) ) , ( iota x E. f ( f : ( 1 ... ( # ` W ) ) -1-1-onto-> W /\ x = ( seq 1 ( .+ , ( F o. f ) ) ` ( # ` W ) ) ) ) ) ) | 
						
							| 95 | 44 47 94 | ifbieq12d |  |-  ( ( ( ph /\ ( w = G /\ g = F ) ) /\ o = O ) -> if ( ran g C_ o , ( 0g ` w ) , if ( dom g e. ran ... , ( iota x E. m E. n e. ( ZZ>= ` m ) ( dom g = ( m ... n ) /\ x = ( seq m ( ( +g ` w ) , g ) ` n ) ) ) , ( iota x E. f [. ( `' g " ( _V \ o ) ) / y ]. ( f : ( 1 ... ( # ` y ) ) -1-1-onto-> y /\ x = ( seq 1 ( ( +g ` w ) , ( g o. f ) ) ` ( # ` y ) ) ) ) ) ) = if ( ran F C_ O , .0. , if ( A e. ran ... , ( iota x E. m E. n e. ( ZZ>= ` m ) ( A = ( m ... n ) /\ x = ( seq m ( .+ , F ) ` n ) ) ) , ( iota x E. f ( f : ( 1 ... ( # ` W ) ) -1-1-onto-> W /\ x = ( seq 1 ( .+ , ( F o. f ) ) ` ( # ` W ) ) ) ) ) ) ) | 
						
							| 96 | 40 95 | csbied |  |-  ( ( ph /\ ( w = G /\ g = F ) ) -> [_ O / o ]_ if ( ran g C_ o , ( 0g ` w ) , if ( dom g e. ran ... , ( iota x E. m E. n e. ( ZZ>= ` m ) ( dom g = ( m ... n ) /\ x = ( seq m ( ( +g ` w ) , g ) ` n ) ) ) , ( iota x E. f [. ( `' g " ( _V \ o ) ) / y ]. ( f : ( 1 ... ( # ` y ) ) -1-1-onto-> y /\ x = ( seq 1 ( ( +g ` w ) , ( g o. f ) ) ` ( # ` y ) ) ) ) ) ) = if ( ran F C_ O , .0. , if ( A e. ran ... , ( iota x E. m E. n e. ( ZZ>= ` m ) ( A = ( m ... n ) /\ x = ( seq m ( .+ , F ) ` n ) ) ) , ( iota x E. f ( f : ( 1 ... ( # ` W ) ) -1-1-onto-> W /\ x = ( seq 1 ( .+ , ( F o. f ) ) ` ( # ` W ) ) ) ) ) ) ) | 
						
							| 97 | 37 96 | eqtrd |  |-  ( ( ph /\ ( w = G /\ g = F ) ) -> [_ { x e. ( Base ` w ) | A. y e. ( Base ` w ) ( ( x ( +g ` w ) y ) = y /\ ( y ( +g ` w ) x ) = y ) } / o ]_ if ( ran g C_ o , ( 0g ` w ) , if ( dom g e. ran ... , ( iota x E. m E. n e. ( ZZ>= ` m ) ( dom g = ( m ... n ) /\ x = ( seq m ( ( +g ` w ) , g ) ` n ) ) ) , ( iota x E. f [. ( `' g " ( _V \ o ) ) / y ]. ( f : ( 1 ... ( # ` y ) ) -1-1-onto-> y /\ x = ( seq 1 ( ( +g ` w ) , ( g o. f ) ) ` ( # ` y ) ) ) ) ) ) = if ( ran F C_ O , .0. , if ( A e. ran ... , ( iota x E. m E. n e. ( ZZ>= ` m ) ( A = ( m ... n ) /\ x = ( seq m ( .+ , F ) ` n ) ) ) , ( iota x E. f ( f : ( 1 ... ( # ` W ) ) -1-1-onto-> W /\ x = ( seq 1 ( .+ , ( F o. f ) ) ` ( # ` W ) ) ) ) ) ) ) | 
						
							| 98 | 6 | elexd |  |-  ( ph -> G e. _V ) | 
						
							| 99 | 7 | elexd |  |-  ( ph -> F e. _V ) | 
						
							| 100 | 2 | fvexi |  |-  .0. e. _V | 
						
							| 101 |  | iotaex |  |-  ( iota x E. m E. n e. ( ZZ>= ` m ) ( A = ( m ... n ) /\ x = ( seq m ( .+ , F ) ` n ) ) ) e. _V | 
						
							| 102 |  | iotaex |  |-  ( iota x E. f ( f : ( 1 ... ( # ` W ) ) -1-1-onto-> W /\ x = ( seq 1 ( .+ , ( F o. f ) ) ` ( # ` W ) ) ) ) e. _V | 
						
							| 103 | 101 102 | ifex |  |-  if ( A e. ran ... , ( iota x E. m E. n e. ( ZZ>= ` m ) ( A = ( m ... n ) /\ x = ( seq m ( .+ , F ) ` n ) ) ) , ( iota x E. f ( f : ( 1 ... ( # ` W ) ) -1-1-onto-> W /\ x = ( seq 1 ( .+ , ( F o. f ) ) ` ( # ` W ) ) ) ) ) e. _V | 
						
							| 104 | 100 103 | ifex |  |-  if ( ran F C_ O , .0. , if ( A e. ran ... , ( iota x E. m E. n e. ( ZZ>= ` m ) ( A = ( m ... n ) /\ x = ( seq m ( .+ , F ) ` n ) ) ) , ( iota x E. f ( f : ( 1 ... ( # ` W ) ) -1-1-onto-> W /\ x = ( seq 1 ( .+ , ( F o. f ) ) ` ( # ` W ) ) ) ) ) ) e. _V | 
						
							| 105 | 104 | a1i |  |-  ( ph -> if ( ran F C_ O , .0. , if ( A e. ran ... , ( iota x E. m E. n e. ( ZZ>= ` m ) ( A = ( m ... n ) /\ x = ( seq m ( .+ , F ) ` n ) ) ) , ( iota x E. f ( f : ( 1 ... ( # ` W ) ) -1-1-onto-> W /\ x = ( seq 1 ( .+ , ( F o. f ) ) ` ( # ` W ) ) ) ) ) ) e. _V ) | 
						
							| 106 | 10 97 98 99 105 | ovmpod |  |-  ( ph -> ( G gsum F ) = if ( ran F C_ O , .0. , if ( A e. ran ... , ( iota x E. m E. n e. ( ZZ>= ` m ) ( A = ( m ... n ) /\ x = ( seq m ( .+ , F ) ` n ) ) ) , ( iota x E. f ( f : ( 1 ... ( # ` W ) ) -1-1-onto-> W /\ x = ( seq 1 ( .+ , ( F o. f ) ) ` ( # ` W ) ) ) ) ) ) ) |