| Step | Hyp | Ref | Expression | 
						
							| 1 |  | frgpup.b |  |-  B = ( Base ` H ) | 
						
							| 2 |  | frgpup.n |  |-  N = ( invg ` H ) | 
						
							| 3 |  | frgpup.t |  |-  T = ( y e. I , z e. 2o |-> if ( z = (/) , ( F ` y ) , ( N ` ( F ` y ) ) ) ) | 
						
							| 4 |  | frgpup.h |  |-  ( ph -> H e. Grp ) | 
						
							| 5 |  | frgpup.i |  |-  ( ph -> I e. V ) | 
						
							| 6 |  | frgpup.a |  |-  ( ph -> F : I --> B ) | 
						
							| 7 |  | frgpup.w |  |-  W = ( _I ` Word ( I X. 2o ) ) | 
						
							| 8 |  | frgpup.r |  |-  .~ = ( ~FG ` I ) | 
						
							| 9 |  | frgpup.g |  |-  G = ( freeGrp ` I ) | 
						
							| 10 |  | frgpup.x |  |-  X = ( Base ` G ) | 
						
							| 11 |  | frgpup.e |  |-  E = ran ( g e. W |-> <. [ g ] .~ , ( H gsum ( T o. g ) ) >. ) | 
						
							| 12 |  | eqid |  |-  ( +g ` G ) = ( +g ` G ) | 
						
							| 13 |  | eqid |  |-  ( +g ` H ) = ( +g ` H ) | 
						
							| 14 | 9 | frgpgrp |  |-  ( I e. V -> G e. Grp ) | 
						
							| 15 | 5 14 | syl |  |-  ( ph -> G e. Grp ) | 
						
							| 16 | 1 2 3 4 5 6 7 8 9 10 11 | frgpupf |  |-  ( ph -> E : X --> B ) | 
						
							| 17 |  | eqid |  |-  ( freeMnd ` ( I X. 2o ) ) = ( freeMnd ` ( I X. 2o ) ) | 
						
							| 18 | 9 17 8 | frgpval |  |-  ( I e. V -> G = ( ( freeMnd ` ( I X. 2o ) ) /s .~ ) ) | 
						
							| 19 | 5 18 | syl |  |-  ( ph -> G = ( ( freeMnd ` ( I X. 2o ) ) /s .~ ) ) | 
						
							| 20 |  | 2on |  |-  2o e. On | 
						
							| 21 |  | xpexg |  |-  ( ( I e. V /\ 2o e. On ) -> ( I X. 2o ) e. _V ) | 
						
							| 22 | 5 20 21 | sylancl |  |-  ( ph -> ( I X. 2o ) e. _V ) | 
						
							| 23 |  | wrdexg |  |-  ( ( I X. 2o ) e. _V -> Word ( I X. 2o ) e. _V ) | 
						
							| 24 |  | fvi |  |-  ( Word ( I X. 2o ) e. _V -> ( _I ` Word ( I X. 2o ) ) = Word ( I X. 2o ) ) | 
						
							| 25 | 22 23 24 | 3syl |  |-  ( ph -> ( _I ` Word ( I X. 2o ) ) = Word ( I X. 2o ) ) | 
						
							| 26 | 7 25 | eqtrid |  |-  ( ph -> W = Word ( I X. 2o ) ) | 
						
							| 27 |  | eqid |  |-  ( Base ` ( freeMnd ` ( I X. 2o ) ) ) = ( Base ` ( freeMnd ` ( I X. 2o ) ) ) | 
						
							| 28 | 17 27 | frmdbas |  |-  ( ( I X. 2o ) e. _V -> ( Base ` ( freeMnd ` ( I X. 2o ) ) ) = Word ( I X. 2o ) ) | 
						
							| 29 | 22 28 | syl |  |-  ( ph -> ( Base ` ( freeMnd ` ( I X. 2o ) ) ) = Word ( I X. 2o ) ) | 
						
							| 30 | 26 29 | eqtr4d |  |-  ( ph -> W = ( Base ` ( freeMnd ` ( I X. 2o ) ) ) ) | 
						
							| 31 | 8 | fvexi |  |-  .~ e. _V | 
						
							| 32 | 31 | a1i |  |-  ( ph -> .~ e. _V ) | 
						
							| 33 |  | fvexd |  |-  ( ph -> ( freeMnd ` ( I X. 2o ) ) e. _V ) | 
						
							| 34 | 19 30 32 33 | qusbas |  |-  ( ph -> ( W /. .~ ) = ( Base ` G ) ) | 
						
							| 35 | 10 34 | eqtr4id |  |-  ( ph -> X = ( W /. .~ ) ) | 
						
							| 36 |  | eqimss |  |-  ( X = ( W /. .~ ) -> X C_ ( W /. .~ ) ) | 
						
							| 37 | 35 36 | syl |  |-  ( ph -> X C_ ( W /. .~ ) ) | 
						
							| 38 | 37 | adantr |  |-  ( ( ph /\ a e. X ) -> X C_ ( W /. .~ ) ) | 
						
							| 39 | 38 | sselda |  |-  ( ( ( ph /\ a e. X ) /\ c e. X ) -> c e. ( W /. .~ ) ) | 
						
							| 40 |  | eqid |  |-  ( W /. .~ ) = ( W /. .~ ) | 
						
							| 41 |  | oveq2 |  |-  ( [ u ] .~ = c -> ( a ( +g ` G ) [ u ] .~ ) = ( a ( +g ` G ) c ) ) | 
						
							| 42 | 41 | fveq2d |  |-  ( [ u ] .~ = c -> ( E ` ( a ( +g ` G ) [ u ] .~ ) ) = ( E ` ( a ( +g ` G ) c ) ) ) | 
						
							| 43 |  | fveq2 |  |-  ( [ u ] .~ = c -> ( E ` [ u ] .~ ) = ( E ` c ) ) | 
						
							| 44 | 43 | oveq2d |  |-  ( [ u ] .~ = c -> ( ( E ` a ) ( +g ` H ) ( E ` [ u ] .~ ) ) = ( ( E ` a ) ( +g ` H ) ( E ` c ) ) ) | 
						
							| 45 | 42 44 | eqeq12d |  |-  ( [ u ] .~ = c -> ( ( E ` ( a ( +g ` G ) [ u ] .~ ) ) = ( ( E ` a ) ( +g ` H ) ( E ` [ u ] .~ ) ) <-> ( E ` ( a ( +g ` G ) c ) ) = ( ( E ` a ) ( +g ` H ) ( E ` c ) ) ) ) | 
						
							| 46 | 37 | sselda |  |-  ( ( ph /\ a e. X ) -> a e. ( W /. .~ ) ) | 
						
							| 47 | 46 | adantlr |  |-  ( ( ( ph /\ u e. W ) /\ a e. X ) -> a e. ( W /. .~ ) ) | 
						
							| 48 |  | fvoveq1 |  |-  ( [ t ] .~ = a -> ( E ` ( [ t ] .~ ( +g ` G ) [ u ] .~ ) ) = ( E ` ( a ( +g ` G ) [ u ] .~ ) ) ) | 
						
							| 49 |  | fveq2 |  |-  ( [ t ] .~ = a -> ( E ` [ t ] .~ ) = ( E ` a ) ) | 
						
							| 50 | 49 | oveq1d |  |-  ( [ t ] .~ = a -> ( ( E ` [ t ] .~ ) ( +g ` H ) ( E ` [ u ] .~ ) ) = ( ( E ` a ) ( +g ` H ) ( E ` [ u ] .~ ) ) ) | 
						
							| 51 | 48 50 | eqeq12d |  |-  ( [ t ] .~ = a -> ( ( E ` ( [ t ] .~ ( +g ` G ) [ u ] .~ ) ) = ( ( E ` [ t ] .~ ) ( +g ` H ) ( E ` [ u ] .~ ) ) <-> ( E ` ( a ( +g ` G ) [ u ] .~ ) ) = ( ( E ` a ) ( +g ` H ) ( E ` [ u ] .~ ) ) ) ) | 
						
							| 52 |  | fviss |  |-  ( _I ` Word ( I X. 2o ) ) C_ Word ( I X. 2o ) | 
						
							| 53 | 7 52 | eqsstri |  |-  W C_ Word ( I X. 2o ) | 
						
							| 54 | 53 | sseli |  |-  ( t e. W -> t e. Word ( I X. 2o ) ) | 
						
							| 55 | 53 | sseli |  |-  ( u e. W -> u e. Word ( I X. 2o ) ) | 
						
							| 56 |  | ccatcl |  |-  ( ( t e. Word ( I X. 2o ) /\ u e. Word ( I X. 2o ) ) -> ( t ++ u ) e. Word ( I X. 2o ) ) | 
						
							| 57 | 54 55 56 | syl2an |  |-  ( ( t e. W /\ u e. W ) -> ( t ++ u ) e. Word ( I X. 2o ) ) | 
						
							| 58 | 7 | efgrcl |  |-  ( t e. W -> ( I e. _V /\ W = Word ( I X. 2o ) ) ) | 
						
							| 59 | 58 | adantr |  |-  ( ( t e. W /\ u e. W ) -> ( I e. _V /\ W = Word ( I X. 2o ) ) ) | 
						
							| 60 | 59 | simprd |  |-  ( ( t e. W /\ u e. W ) -> W = Word ( I X. 2o ) ) | 
						
							| 61 | 57 60 | eleqtrrd |  |-  ( ( t e. W /\ u e. W ) -> ( t ++ u ) e. W ) | 
						
							| 62 | 1 2 3 4 5 6 7 8 9 10 11 | frgpupval |  |-  ( ( ph /\ ( t ++ u ) e. W ) -> ( E ` [ ( t ++ u ) ] .~ ) = ( H gsum ( T o. ( t ++ u ) ) ) ) | 
						
							| 63 | 61 62 | sylan2 |  |-  ( ( ph /\ ( t e. W /\ u e. W ) ) -> ( E ` [ ( t ++ u ) ] .~ ) = ( H gsum ( T o. ( t ++ u ) ) ) ) | 
						
							| 64 | 54 | ad2antrl |  |-  ( ( ph /\ ( t e. W /\ u e. W ) ) -> t e. Word ( I X. 2o ) ) | 
						
							| 65 | 55 | ad2antll |  |-  ( ( ph /\ ( t e. W /\ u e. W ) ) -> u e. Word ( I X. 2o ) ) | 
						
							| 66 | 1 2 3 4 5 6 | frgpuptf |  |-  ( ph -> T : ( I X. 2o ) --> B ) | 
						
							| 67 | 66 | adantr |  |-  ( ( ph /\ ( t e. W /\ u e. W ) ) -> T : ( I X. 2o ) --> B ) | 
						
							| 68 |  | ccatco |  |-  ( ( t e. Word ( I X. 2o ) /\ u e. Word ( I X. 2o ) /\ T : ( I X. 2o ) --> B ) -> ( T o. ( t ++ u ) ) = ( ( T o. t ) ++ ( T o. u ) ) ) | 
						
							| 69 | 64 65 67 68 | syl3anc |  |-  ( ( ph /\ ( t e. W /\ u e. W ) ) -> ( T o. ( t ++ u ) ) = ( ( T o. t ) ++ ( T o. u ) ) ) | 
						
							| 70 | 69 | oveq2d |  |-  ( ( ph /\ ( t e. W /\ u e. W ) ) -> ( H gsum ( T o. ( t ++ u ) ) ) = ( H gsum ( ( T o. t ) ++ ( T o. u ) ) ) ) | 
						
							| 71 | 4 | grpmndd |  |-  ( ph -> H e. Mnd ) | 
						
							| 72 | 71 | adantr |  |-  ( ( ph /\ ( t e. W /\ u e. W ) ) -> H e. Mnd ) | 
						
							| 73 |  | wrdco |  |-  ( ( t e. Word ( I X. 2o ) /\ T : ( I X. 2o ) --> B ) -> ( T o. t ) e. Word B ) | 
						
							| 74 | 54 66 73 | syl2anr |  |-  ( ( ph /\ t e. W ) -> ( T o. t ) e. Word B ) | 
						
							| 75 | 74 | adantrr |  |-  ( ( ph /\ ( t e. W /\ u e. W ) ) -> ( T o. t ) e. Word B ) | 
						
							| 76 |  | wrdco |  |-  ( ( u e. Word ( I X. 2o ) /\ T : ( I X. 2o ) --> B ) -> ( T o. u ) e. Word B ) | 
						
							| 77 | 65 67 76 | syl2anc |  |-  ( ( ph /\ ( t e. W /\ u e. W ) ) -> ( T o. u ) e. Word B ) | 
						
							| 78 | 1 13 | gsumccat |  |-  ( ( H e. Mnd /\ ( T o. t ) e. Word B /\ ( T o. u ) e. Word B ) -> ( H gsum ( ( T o. t ) ++ ( T o. u ) ) ) = ( ( H gsum ( T o. t ) ) ( +g ` H ) ( H gsum ( T o. u ) ) ) ) | 
						
							| 79 | 72 75 77 78 | syl3anc |  |-  ( ( ph /\ ( t e. W /\ u e. W ) ) -> ( H gsum ( ( T o. t ) ++ ( T o. u ) ) ) = ( ( H gsum ( T o. t ) ) ( +g ` H ) ( H gsum ( T o. u ) ) ) ) | 
						
							| 80 | 63 70 79 | 3eqtrd |  |-  ( ( ph /\ ( t e. W /\ u e. W ) ) -> ( E ` [ ( t ++ u ) ] .~ ) = ( ( H gsum ( T o. t ) ) ( +g ` H ) ( H gsum ( T o. u ) ) ) ) | 
						
							| 81 | 7 9 8 12 | frgpadd |  |-  ( ( t e. W /\ u e. W ) -> ( [ t ] .~ ( +g ` G ) [ u ] .~ ) = [ ( t ++ u ) ] .~ ) | 
						
							| 82 | 81 | adantl |  |-  ( ( ph /\ ( t e. W /\ u e. W ) ) -> ( [ t ] .~ ( +g ` G ) [ u ] .~ ) = [ ( t ++ u ) ] .~ ) | 
						
							| 83 | 82 | fveq2d |  |-  ( ( ph /\ ( t e. W /\ u e. W ) ) -> ( E ` ( [ t ] .~ ( +g ` G ) [ u ] .~ ) ) = ( E ` [ ( t ++ u ) ] .~ ) ) | 
						
							| 84 | 1 2 3 4 5 6 7 8 9 10 11 | frgpupval |  |-  ( ( ph /\ t e. W ) -> ( E ` [ t ] .~ ) = ( H gsum ( T o. t ) ) ) | 
						
							| 85 | 84 | adantrr |  |-  ( ( ph /\ ( t e. W /\ u e. W ) ) -> ( E ` [ t ] .~ ) = ( H gsum ( T o. t ) ) ) | 
						
							| 86 | 1 2 3 4 5 6 7 8 9 10 11 | frgpupval |  |-  ( ( ph /\ u e. W ) -> ( E ` [ u ] .~ ) = ( H gsum ( T o. u ) ) ) | 
						
							| 87 | 86 | adantrl |  |-  ( ( ph /\ ( t e. W /\ u e. W ) ) -> ( E ` [ u ] .~ ) = ( H gsum ( T o. u ) ) ) | 
						
							| 88 | 85 87 | oveq12d |  |-  ( ( ph /\ ( t e. W /\ u e. W ) ) -> ( ( E ` [ t ] .~ ) ( +g ` H ) ( E ` [ u ] .~ ) ) = ( ( H gsum ( T o. t ) ) ( +g ` H ) ( H gsum ( T o. u ) ) ) ) | 
						
							| 89 | 80 83 88 | 3eqtr4d |  |-  ( ( ph /\ ( t e. W /\ u e. W ) ) -> ( E ` ( [ t ] .~ ( +g ` G ) [ u ] .~ ) ) = ( ( E ` [ t ] .~ ) ( +g ` H ) ( E ` [ u ] .~ ) ) ) | 
						
							| 90 | 89 | anass1rs |  |-  ( ( ( ph /\ u e. W ) /\ t e. W ) -> ( E ` ( [ t ] .~ ( +g ` G ) [ u ] .~ ) ) = ( ( E ` [ t ] .~ ) ( +g ` H ) ( E ` [ u ] .~ ) ) ) | 
						
							| 91 | 40 51 90 | ectocld |  |-  ( ( ( ph /\ u e. W ) /\ a e. ( W /. .~ ) ) -> ( E ` ( a ( +g ` G ) [ u ] .~ ) ) = ( ( E ` a ) ( +g ` H ) ( E ` [ u ] .~ ) ) ) | 
						
							| 92 | 47 91 | syldan |  |-  ( ( ( ph /\ u e. W ) /\ a e. X ) -> ( E ` ( a ( +g ` G ) [ u ] .~ ) ) = ( ( E ` a ) ( +g ` H ) ( E ` [ u ] .~ ) ) ) | 
						
							| 93 | 92 | an32s |  |-  ( ( ( ph /\ a e. X ) /\ u e. W ) -> ( E ` ( a ( +g ` G ) [ u ] .~ ) ) = ( ( E ` a ) ( +g ` H ) ( E ` [ u ] .~ ) ) ) | 
						
							| 94 | 40 45 93 | ectocld |  |-  ( ( ( ph /\ a e. X ) /\ c e. ( W /. .~ ) ) -> ( E ` ( a ( +g ` G ) c ) ) = ( ( E ` a ) ( +g ` H ) ( E ` c ) ) ) | 
						
							| 95 | 39 94 | syldan |  |-  ( ( ( ph /\ a e. X ) /\ c e. X ) -> ( E ` ( a ( +g ` G ) c ) ) = ( ( E ` a ) ( +g ` H ) ( E ` c ) ) ) | 
						
							| 96 | 95 | anasss |  |-  ( ( ph /\ ( a e. X /\ c e. X ) ) -> ( E ` ( a ( +g ` G ) c ) ) = ( ( E ` a ) ( +g ` H ) ( E ` c ) ) ) | 
						
							| 97 | 10 1 12 13 15 4 16 96 | isghmd |  |-  ( ph -> E e. ( G GrpHom H ) ) |