| Step | Hyp | Ref | Expression | 
						
							| 1 |  | frgpnabl.g |  |-  G = ( freeGrp ` I ) | 
						
							| 2 |  | frgpnabl.w |  |-  W = ( _I ` Word ( I X. 2o ) ) | 
						
							| 3 |  | frgpnabl.r |  |-  .~ = ( ~FG ` I ) | 
						
							| 4 |  | frgpnabl.p |  |-  .+ = ( +g ` G ) | 
						
							| 5 |  | frgpnabl.m |  |-  M = ( y e. I , z e. 2o |-> <. y , ( 1o \ z ) >. ) | 
						
							| 6 |  | frgpnabl.t |  |-  T = ( v e. W |-> ( n e. ( 0 ... ( # ` v ) ) , w e. ( I X. 2o ) |-> ( v splice <. n , n , <" w ( M ` w ) "> >. ) ) ) | 
						
							| 7 |  | frgpnabl.d |  |-  D = ( W \ U_ x e. W ran ( T ` x ) ) | 
						
							| 8 |  | frgpnabl.u |  |-  U = ( varFGrp ` I ) | 
						
							| 9 |  | frgpnabl.i |  |-  ( ph -> I e. V ) | 
						
							| 10 |  | frgpnabl.a |  |-  ( ph -> A e. I ) | 
						
							| 11 |  | frgpnabl.b |  |-  ( ph -> B e. I ) | 
						
							| 12 |  | frgpnabl.n |  |-  ( ph -> ( ( U ` A ) .+ ( U ` B ) ) = ( ( U ` B ) .+ ( U ` A ) ) ) | 
						
							| 13 |  | 0ex |  |-  (/) e. _V | 
						
							| 14 | 13 | a1i |  |-  ( ph -> (/) e. _V ) | 
						
							| 15 |  | difss |  |-  ( W \ U_ x e. W ran ( T ` x ) ) C_ W | 
						
							| 16 | 7 15 | eqsstri |  |-  D C_ W | 
						
							| 17 | 1 2 3 4 5 6 7 8 9 11 10 | frgpnabllem1 |  |-  ( ph -> <" <. B , (/) >. <. A , (/) >. "> e. ( D i^i ( ( U ` B ) .+ ( U ` A ) ) ) ) | 
						
							| 18 | 17 | elin1d |  |-  ( ph -> <" <. B , (/) >. <. A , (/) >. "> e. D ) | 
						
							| 19 | 16 18 | sselid |  |-  ( ph -> <" <. B , (/) >. <. A , (/) >. "> e. W ) | 
						
							| 20 |  | eqid |  |-  ( m e. { t e. ( Word W \ { (/) } ) | ( ( t ` 0 ) e. D /\ A. k e. ( 1 ..^ ( # ` t ) ) ( t ` k ) e. ran ( T ` ( t ` ( k - 1 ) ) ) ) } |-> ( m ` ( ( # ` m ) - 1 ) ) ) = ( m e. { t e. ( Word W \ { (/) } ) | ( ( t ` 0 ) e. D /\ A. k e. ( 1 ..^ ( # ` t ) ) ( t ` k ) e. ran ( T ` ( t ` ( k - 1 ) ) ) ) } |-> ( m ` ( ( # ` m ) - 1 ) ) ) | 
						
							| 21 | 2 3 5 6 7 20 | efgredeu |  |-  ( <" <. B , (/) >. <. A , (/) >. "> e. W -> E! d e. D d .~ <" <. B , (/) >. <. A , (/) >. "> ) | 
						
							| 22 |  | reurmo |  |-  ( E! d e. D d .~ <" <. B , (/) >. <. A , (/) >. "> -> E* d e. D d .~ <" <. B , (/) >. <. A , (/) >. "> ) | 
						
							| 23 | 19 21 22 | 3syl |  |-  ( ph -> E* d e. D d .~ <" <. B , (/) >. <. A , (/) >. "> ) | 
						
							| 24 | 1 2 3 4 5 6 7 8 9 10 11 | frgpnabllem1 |  |-  ( ph -> <" <. A , (/) >. <. B , (/) >. "> e. ( D i^i ( ( U ` A ) .+ ( U ` B ) ) ) ) | 
						
							| 25 | 24 | elin1d |  |-  ( ph -> <" <. A , (/) >. <. B , (/) >. "> e. D ) | 
						
							| 26 | 2 3 | efger |  |-  .~ Er W | 
						
							| 27 | 26 | a1i |  |-  ( ph -> .~ Er W ) | 
						
							| 28 | 1 | frgpgrp |  |-  ( I e. V -> G e. Grp ) | 
						
							| 29 | 9 28 | syl |  |-  ( ph -> G e. Grp ) | 
						
							| 30 |  | eqid |  |-  ( Base ` G ) = ( Base ` G ) | 
						
							| 31 | 3 8 1 30 | vrgpf |  |-  ( I e. V -> U : I --> ( Base ` G ) ) | 
						
							| 32 | 9 31 | syl |  |-  ( ph -> U : I --> ( Base ` G ) ) | 
						
							| 33 | 32 10 | ffvelcdmd |  |-  ( ph -> ( U ` A ) e. ( Base ` G ) ) | 
						
							| 34 | 32 11 | ffvelcdmd |  |-  ( ph -> ( U ` B ) e. ( Base ` G ) ) | 
						
							| 35 | 30 4 | grpcl |  |-  ( ( G e. Grp /\ ( U ` A ) e. ( Base ` G ) /\ ( U ` B ) e. ( Base ` G ) ) -> ( ( U ` A ) .+ ( U ` B ) ) e. ( Base ` G ) ) | 
						
							| 36 | 29 33 34 35 | syl3anc |  |-  ( ph -> ( ( U ` A ) .+ ( U ` B ) ) e. ( Base ` G ) ) | 
						
							| 37 |  | eqid |  |-  ( freeMnd ` ( I X. 2o ) ) = ( freeMnd ` ( I X. 2o ) ) | 
						
							| 38 | 1 37 3 | frgpval |  |-  ( I e. V -> G = ( ( freeMnd ` ( I X. 2o ) ) /s .~ ) ) | 
						
							| 39 | 9 38 | syl |  |-  ( ph -> G = ( ( freeMnd ` ( I X. 2o ) ) /s .~ ) ) | 
						
							| 40 |  | 2on |  |-  2o e. On | 
						
							| 41 |  | xpexg |  |-  ( ( I e. V /\ 2o e. On ) -> ( I X. 2o ) e. _V ) | 
						
							| 42 | 9 40 41 | sylancl |  |-  ( ph -> ( I X. 2o ) e. _V ) | 
						
							| 43 |  | wrdexg |  |-  ( ( I X. 2o ) e. _V -> Word ( I X. 2o ) e. _V ) | 
						
							| 44 |  | fvi |  |-  ( Word ( I X. 2o ) e. _V -> ( _I ` Word ( I X. 2o ) ) = Word ( I X. 2o ) ) | 
						
							| 45 | 42 43 44 | 3syl |  |-  ( ph -> ( _I ` Word ( I X. 2o ) ) = Word ( I X. 2o ) ) | 
						
							| 46 | 2 45 | eqtrid |  |-  ( ph -> W = Word ( I X. 2o ) ) | 
						
							| 47 |  | eqid |  |-  ( Base ` ( freeMnd ` ( I X. 2o ) ) ) = ( Base ` ( freeMnd ` ( I X. 2o ) ) ) | 
						
							| 48 | 37 47 | frmdbas |  |-  ( ( I X. 2o ) e. _V -> ( Base ` ( freeMnd ` ( I X. 2o ) ) ) = Word ( I X. 2o ) ) | 
						
							| 49 | 42 48 | syl |  |-  ( ph -> ( Base ` ( freeMnd ` ( I X. 2o ) ) ) = Word ( I X. 2o ) ) | 
						
							| 50 | 46 49 | eqtr4d |  |-  ( ph -> W = ( Base ` ( freeMnd ` ( I X. 2o ) ) ) ) | 
						
							| 51 | 3 | fvexi |  |-  .~ e. _V | 
						
							| 52 | 51 | a1i |  |-  ( ph -> .~ e. _V ) | 
						
							| 53 |  | fvexd |  |-  ( ph -> ( freeMnd ` ( I X. 2o ) ) e. _V ) | 
						
							| 54 | 39 50 52 53 | qusbas |  |-  ( ph -> ( W /. .~ ) = ( Base ` G ) ) | 
						
							| 55 | 36 54 | eleqtrrd |  |-  ( ph -> ( ( U ` A ) .+ ( U ` B ) ) e. ( W /. .~ ) ) | 
						
							| 56 | 24 | elin2d |  |-  ( ph -> <" <. A , (/) >. <. B , (/) >. "> e. ( ( U ` A ) .+ ( U ` B ) ) ) | 
						
							| 57 |  | qsel |  |-  ( ( .~ Er W /\ ( ( U ` A ) .+ ( U ` B ) ) e. ( W /. .~ ) /\ <" <. A , (/) >. <. B , (/) >. "> e. ( ( U ` A ) .+ ( U ` B ) ) ) -> ( ( U ` A ) .+ ( U ` B ) ) = [ <" <. A , (/) >. <. B , (/) >. "> ] .~ ) | 
						
							| 58 | 27 55 56 57 | syl3anc |  |-  ( ph -> ( ( U ` A ) .+ ( U ` B ) ) = [ <" <. A , (/) >. <. B , (/) >. "> ] .~ ) | 
						
							| 59 | 17 | elin2d |  |-  ( ph -> <" <. B , (/) >. <. A , (/) >. "> e. ( ( U ` B ) .+ ( U ` A ) ) ) | 
						
							| 60 | 59 12 | eleqtrrd |  |-  ( ph -> <" <. B , (/) >. <. A , (/) >. "> e. ( ( U ` A ) .+ ( U ` B ) ) ) | 
						
							| 61 |  | qsel |  |-  ( ( .~ Er W /\ ( ( U ` A ) .+ ( U ` B ) ) e. ( W /. .~ ) /\ <" <. B , (/) >. <. A , (/) >. "> e. ( ( U ` A ) .+ ( U ` B ) ) ) -> ( ( U ` A ) .+ ( U ` B ) ) = [ <" <. B , (/) >. <. A , (/) >. "> ] .~ ) | 
						
							| 62 | 27 55 60 61 | syl3anc |  |-  ( ph -> ( ( U ` A ) .+ ( U ` B ) ) = [ <" <. B , (/) >. <. A , (/) >. "> ] .~ ) | 
						
							| 63 | 58 62 | eqtr3d |  |-  ( ph -> [ <" <. A , (/) >. <. B , (/) >. "> ] .~ = [ <" <. B , (/) >. <. A , (/) >. "> ] .~ ) | 
						
							| 64 | 16 25 | sselid |  |-  ( ph -> <" <. A , (/) >. <. B , (/) >. "> e. W ) | 
						
							| 65 | 27 64 | erth |  |-  ( ph -> ( <" <. A , (/) >. <. B , (/) >. "> .~ <" <. B , (/) >. <. A , (/) >. "> <-> [ <" <. A , (/) >. <. B , (/) >. "> ] .~ = [ <" <. B , (/) >. <. A , (/) >. "> ] .~ ) ) | 
						
							| 66 | 63 65 | mpbird |  |-  ( ph -> <" <. A , (/) >. <. B , (/) >. "> .~ <" <. B , (/) >. <. A , (/) >. "> ) | 
						
							| 67 | 27 19 | erref |  |-  ( ph -> <" <. B , (/) >. <. A , (/) >. "> .~ <" <. B , (/) >. <. A , (/) >. "> ) | 
						
							| 68 |  | breq1 |  |-  ( d = <" <. A , (/) >. <. B , (/) >. "> -> ( d .~ <" <. B , (/) >. <. A , (/) >. "> <-> <" <. A , (/) >. <. B , (/) >. "> .~ <" <. B , (/) >. <. A , (/) >. "> ) ) | 
						
							| 69 |  | breq1 |  |-  ( d = <" <. B , (/) >. <. A , (/) >. "> -> ( d .~ <" <. B , (/) >. <. A , (/) >. "> <-> <" <. B , (/) >. <. A , (/) >. "> .~ <" <. B , (/) >. <. A , (/) >. "> ) ) | 
						
							| 70 | 68 69 | rmoi |  |-  ( ( E* d e. D d .~ <" <. B , (/) >. <. A , (/) >. "> /\ ( <" <. A , (/) >. <. B , (/) >. "> e. D /\ <" <. A , (/) >. <. B , (/) >. "> .~ <" <. B , (/) >. <. A , (/) >. "> ) /\ ( <" <. B , (/) >. <. A , (/) >. "> e. D /\ <" <. B , (/) >. <. A , (/) >. "> .~ <" <. B , (/) >. <. A , (/) >. "> ) ) -> <" <. A , (/) >. <. B , (/) >. "> = <" <. B , (/) >. <. A , (/) >. "> ) | 
						
							| 71 | 23 25 66 18 67 70 | syl122anc |  |-  ( ph -> <" <. A , (/) >. <. B , (/) >. "> = <" <. B , (/) >. <. A , (/) >. "> ) | 
						
							| 72 | 71 | fveq1d |  |-  ( ph -> ( <" <. A , (/) >. <. B , (/) >. "> ` 0 ) = ( <" <. B , (/) >. <. A , (/) >. "> ` 0 ) ) | 
						
							| 73 |  | opex |  |-  <. A , (/) >. e. _V | 
						
							| 74 |  | s2fv0 |  |-  ( <. A , (/) >. e. _V -> ( <" <. A , (/) >. <. B , (/) >. "> ` 0 ) = <. A , (/) >. ) | 
						
							| 75 | 73 74 | ax-mp |  |-  ( <" <. A , (/) >. <. B , (/) >. "> ` 0 ) = <. A , (/) >. | 
						
							| 76 |  | opex |  |-  <. B , (/) >. e. _V | 
						
							| 77 |  | s2fv0 |  |-  ( <. B , (/) >. e. _V -> ( <" <. B , (/) >. <. A , (/) >. "> ` 0 ) = <. B , (/) >. ) | 
						
							| 78 | 76 77 | ax-mp |  |-  ( <" <. B , (/) >. <. A , (/) >. "> ` 0 ) = <. B , (/) >. | 
						
							| 79 | 72 75 78 | 3eqtr3g |  |-  ( ph -> <. A , (/) >. = <. B , (/) >. ) | 
						
							| 80 |  | opthg |  |-  ( ( A e. I /\ (/) e. _V ) -> ( <. A , (/) >. = <. B , (/) >. <-> ( A = B /\ (/) = (/) ) ) ) | 
						
							| 81 | 80 | simprbda |  |-  ( ( ( A e. I /\ (/) e. _V ) /\ <. A , (/) >. = <. B , (/) >. ) -> A = B ) | 
						
							| 82 | 10 14 79 81 | syl21anc |  |-  ( ph -> A = B ) |