| Step | Hyp | Ref | Expression | 
						
							| 1 |  | odf1.1 |  |-  X = ( Base ` G ) | 
						
							| 2 |  | odf1.2 |  |-  O = ( od ` G ) | 
						
							| 3 |  | odf1.3 |  |-  .x. = ( .g ` G ) | 
						
							| 4 |  | odf1.4 |  |-  F = ( x e. ZZ |-> ( x .x. A ) ) | 
						
							| 5 | 1 3 | mulgcl |  |-  ( ( G e. Grp /\ x e. ZZ /\ A e. X ) -> ( x .x. A ) e. X ) | 
						
							| 6 | 5 | 3expa |  |-  ( ( ( G e. Grp /\ x e. ZZ ) /\ A e. X ) -> ( x .x. A ) e. X ) | 
						
							| 7 | 6 | an32s |  |-  ( ( ( G e. Grp /\ A e. X ) /\ x e. ZZ ) -> ( x .x. A ) e. X ) | 
						
							| 8 | 7 4 | fmptd |  |-  ( ( G e. Grp /\ A e. X ) -> F : ZZ --> X ) | 
						
							| 9 | 8 | adantr |  |-  ( ( ( G e. Grp /\ A e. X ) /\ ( O ` A ) = 0 ) -> F : ZZ --> X ) | 
						
							| 10 |  | oveq1 |  |-  ( x = y -> ( x .x. A ) = ( y .x. A ) ) | 
						
							| 11 |  | ovex |  |-  ( x .x. A ) e. _V | 
						
							| 12 | 10 4 11 | fvmpt3i |  |-  ( y e. ZZ -> ( F ` y ) = ( y .x. A ) ) | 
						
							| 13 |  | oveq1 |  |-  ( x = z -> ( x .x. A ) = ( z .x. A ) ) | 
						
							| 14 | 13 4 11 | fvmpt3i |  |-  ( z e. ZZ -> ( F ` z ) = ( z .x. A ) ) | 
						
							| 15 | 12 14 | eqeqan12d |  |-  ( ( y e. ZZ /\ z e. ZZ ) -> ( ( F ` y ) = ( F ` z ) <-> ( y .x. A ) = ( z .x. A ) ) ) | 
						
							| 16 | 15 | adantl |  |-  ( ( ( ( G e. Grp /\ A e. X ) /\ ( O ` A ) = 0 ) /\ ( y e. ZZ /\ z e. ZZ ) ) -> ( ( F ` y ) = ( F ` z ) <-> ( y .x. A ) = ( z .x. A ) ) ) | 
						
							| 17 |  | simplr |  |-  ( ( ( ( G e. Grp /\ A e. X ) /\ ( O ` A ) = 0 ) /\ ( y e. ZZ /\ z e. ZZ ) ) -> ( O ` A ) = 0 ) | 
						
							| 18 | 17 | breq1d |  |-  ( ( ( ( G e. Grp /\ A e. X ) /\ ( O ` A ) = 0 ) /\ ( y e. ZZ /\ z e. ZZ ) ) -> ( ( O ` A ) || ( y - z ) <-> 0 || ( y - z ) ) ) | 
						
							| 19 |  | eqid |  |-  ( 0g ` G ) = ( 0g ` G ) | 
						
							| 20 | 1 2 3 19 | odcong |  |-  ( ( G e. Grp /\ A e. X /\ ( y e. ZZ /\ z e. ZZ ) ) -> ( ( O ` A ) || ( y - z ) <-> ( y .x. A ) = ( z .x. A ) ) ) | 
						
							| 21 | 20 | ad4ant124 |  |-  ( ( ( ( G e. Grp /\ A e. X ) /\ ( O ` A ) = 0 ) /\ ( y e. ZZ /\ z e. ZZ ) ) -> ( ( O ` A ) || ( y - z ) <-> ( y .x. A ) = ( z .x. A ) ) ) | 
						
							| 22 |  | zsubcl |  |-  ( ( y e. ZZ /\ z e. ZZ ) -> ( y - z ) e. ZZ ) | 
						
							| 23 | 22 | adantl |  |-  ( ( ( ( G e. Grp /\ A e. X ) /\ ( O ` A ) = 0 ) /\ ( y e. ZZ /\ z e. ZZ ) ) -> ( y - z ) e. ZZ ) | 
						
							| 24 |  | 0dvds |  |-  ( ( y - z ) e. ZZ -> ( 0 || ( y - z ) <-> ( y - z ) = 0 ) ) | 
						
							| 25 | 23 24 | syl |  |-  ( ( ( ( G e. Grp /\ A e. X ) /\ ( O ` A ) = 0 ) /\ ( y e. ZZ /\ z e. ZZ ) ) -> ( 0 || ( y - z ) <-> ( y - z ) = 0 ) ) | 
						
							| 26 | 18 21 25 | 3bitr3d |  |-  ( ( ( ( G e. Grp /\ A e. X ) /\ ( O ` A ) = 0 ) /\ ( y e. ZZ /\ z e. ZZ ) ) -> ( ( y .x. A ) = ( z .x. A ) <-> ( y - z ) = 0 ) ) | 
						
							| 27 |  | zcn |  |-  ( y e. ZZ -> y e. CC ) | 
						
							| 28 |  | zcn |  |-  ( z e. ZZ -> z e. CC ) | 
						
							| 29 |  | subeq0 |  |-  ( ( y e. CC /\ z e. CC ) -> ( ( y - z ) = 0 <-> y = z ) ) | 
						
							| 30 | 27 28 29 | syl2an |  |-  ( ( y e. ZZ /\ z e. ZZ ) -> ( ( y - z ) = 0 <-> y = z ) ) | 
						
							| 31 | 30 | adantl |  |-  ( ( ( ( G e. Grp /\ A e. X ) /\ ( O ` A ) = 0 ) /\ ( y e. ZZ /\ z e. ZZ ) ) -> ( ( y - z ) = 0 <-> y = z ) ) | 
						
							| 32 | 16 26 31 | 3bitrd |  |-  ( ( ( ( G e. Grp /\ A e. X ) /\ ( O ` A ) = 0 ) /\ ( y e. ZZ /\ z e. ZZ ) ) -> ( ( F ` y ) = ( F ` z ) <-> y = z ) ) | 
						
							| 33 | 32 | biimpd |  |-  ( ( ( ( G e. Grp /\ A e. X ) /\ ( O ` A ) = 0 ) /\ ( y e. ZZ /\ z e. ZZ ) ) -> ( ( F ` y ) = ( F ` z ) -> y = z ) ) | 
						
							| 34 | 33 | ralrimivva |  |-  ( ( ( G e. Grp /\ A e. X ) /\ ( O ` A ) = 0 ) -> A. y e. ZZ A. z e. ZZ ( ( F ` y ) = ( F ` z ) -> y = z ) ) | 
						
							| 35 |  | dff13 |  |-  ( F : ZZ -1-1-> X <-> ( F : ZZ --> X /\ A. y e. ZZ A. z e. ZZ ( ( F ` y ) = ( F ` z ) -> y = z ) ) ) | 
						
							| 36 | 9 34 35 | sylanbrc |  |-  ( ( ( G e. Grp /\ A e. X ) /\ ( O ` A ) = 0 ) -> F : ZZ -1-1-> X ) | 
						
							| 37 | 1 2 3 19 | odid |  |-  ( A e. X -> ( ( O ` A ) .x. A ) = ( 0g ` G ) ) | 
						
							| 38 | 1 19 3 | mulg0 |  |-  ( A e. X -> ( 0 .x. A ) = ( 0g ` G ) ) | 
						
							| 39 | 37 38 | eqtr4d |  |-  ( A e. X -> ( ( O ` A ) .x. A ) = ( 0 .x. A ) ) | 
						
							| 40 | 39 | ad2antlr |  |-  ( ( ( G e. Grp /\ A e. X ) /\ F : ZZ -1-1-> X ) -> ( ( O ` A ) .x. A ) = ( 0 .x. A ) ) | 
						
							| 41 | 1 2 | odcl |  |-  ( A e. X -> ( O ` A ) e. NN0 ) | 
						
							| 42 | 41 | ad2antlr |  |-  ( ( ( G e. Grp /\ A e. X ) /\ F : ZZ -1-1-> X ) -> ( O ` A ) e. NN0 ) | 
						
							| 43 | 42 | nn0zd |  |-  ( ( ( G e. Grp /\ A e. X ) /\ F : ZZ -1-1-> X ) -> ( O ` A ) e. ZZ ) | 
						
							| 44 |  | oveq1 |  |-  ( x = ( O ` A ) -> ( x .x. A ) = ( ( O ` A ) .x. A ) ) | 
						
							| 45 | 44 4 11 | fvmpt3i |  |-  ( ( O ` A ) e. ZZ -> ( F ` ( O ` A ) ) = ( ( O ` A ) .x. A ) ) | 
						
							| 46 | 43 45 | syl |  |-  ( ( ( G e. Grp /\ A e. X ) /\ F : ZZ -1-1-> X ) -> ( F ` ( O ` A ) ) = ( ( O ` A ) .x. A ) ) | 
						
							| 47 |  | 0zd |  |-  ( ( ( G e. Grp /\ A e. X ) /\ F : ZZ -1-1-> X ) -> 0 e. ZZ ) | 
						
							| 48 |  | oveq1 |  |-  ( x = 0 -> ( x .x. A ) = ( 0 .x. A ) ) | 
						
							| 49 | 48 4 11 | fvmpt3i |  |-  ( 0 e. ZZ -> ( F ` 0 ) = ( 0 .x. A ) ) | 
						
							| 50 | 47 49 | syl |  |-  ( ( ( G e. Grp /\ A e. X ) /\ F : ZZ -1-1-> X ) -> ( F ` 0 ) = ( 0 .x. A ) ) | 
						
							| 51 | 40 46 50 | 3eqtr4d |  |-  ( ( ( G e. Grp /\ A e. X ) /\ F : ZZ -1-1-> X ) -> ( F ` ( O ` A ) ) = ( F ` 0 ) ) | 
						
							| 52 |  | simpr |  |-  ( ( ( G e. Grp /\ A e. X ) /\ F : ZZ -1-1-> X ) -> F : ZZ -1-1-> X ) | 
						
							| 53 |  | f1fveq |  |-  ( ( F : ZZ -1-1-> X /\ ( ( O ` A ) e. ZZ /\ 0 e. ZZ ) ) -> ( ( F ` ( O ` A ) ) = ( F ` 0 ) <-> ( O ` A ) = 0 ) ) | 
						
							| 54 | 52 43 47 53 | syl12anc |  |-  ( ( ( G e. Grp /\ A e. X ) /\ F : ZZ -1-1-> X ) -> ( ( F ` ( O ` A ) ) = ( F ` 0 ) <-> ( O ` A ) = 0 ) ) | 
						
							| 55 | 51 54 | mpbid |  |-  ( ( ( G e. Grp /\ A e. X ) /\ F : ZZ -1-1-> X ) -> ( O ` A ) = 0 ) | 
						
							| 56 | 36 55 | impbida |  |-  ( ( G e. Grp /\ A e. X ) -> ( ( O ` A ) = 0 <-> F : ZZ -1-1-> X ) ) |