| Step | Hyp | Ref | Expression | 
						
							| 1 |  | iscyg.1 |  |-  B = ( Base ` G ) | 
						
							| 2 |  | iscyg.2 |  |-  .x. = ( .g ` G ) | 
						
							| 3 |  | iscyg3.e |  |-  E = { x e. B | ran ( n e. ZZ |-> ( n .x. x ) ) = B } | 
						
							| 4 |  | cyggenod.o |  |-  O = ( od ` G ) | 
						
							| 5 | 1 2 3 | iscyggen |  |-  ( X e. E <-> ( X e. B /\ ran ( n e. ZZ |-> ( n .x. X ) ) = B ) ) | 
						
							| 6 |  | simplr |  |-  ( ( ( G e. Grp /\ B e. Fin ) /\ X e. B ) -> B e. Fin ) | 
						
							| 7 |  | simplll |  |-  ( ( ( ( G e. Grp /\ B e. Fin ) /\ X e. B ) /\ n e. ZZ ) -> G e. Grp ) | 
						
							| 8 |  | simpr |  |-  ( ( ( ( G e. Grp /\ B e. Fin ) /\ X e. B ) /\ n e. ZZ ) -> n e. ZZ ) | 
						
							| 9 |  | simplr |  |-  ( ( ( ( G e. Grp /\ B e. Fin ) /\ X e. B ) /\ n e. ZZ ) -> X e. B ) | 
						
							| 10 | 1 2 | mulgcl |  |-  ( ( G e. Grp /\ n e. ZZ /\ X e. B ) -> ( n .x. X ) e. B ) | 
						
							| 11 | 7 8 9 10 | syl3anc |  |-  ( ( ( ( G e. Grp /\ B e. Fin ) /\ X e. B ) /\ n e. ZZ ) -> ( n .x. X ) e. B ) | 
						
							| 12 | 11 | fmpttd |  |-  ( ( ( G e. Grp /\ B e. Fin ) /\ X e. B ) -> ( n e. ZZ |-> ( n .x. X ) ) : ZZ --> B ) | 
						
							| 13 | 12 | frnd |  |-  ( ( ( G e. Grp /\ B e. Fin ) /\ X e. B ) -> ran ( n e. ZZ |-> ( n .x. X ) ) C_ B ) | 
						
							| 14 | 6 13 | ssfid |  |-  ( ( ( G e. Grp /\ B e. Fin ) /\ X e. B ) -> ran ( n e. ZZ |-> ( n .x. X ) ) e. Fin ) | 
						
							| 15 |  | hashen |  |-  ( ( ran ( n e. ZZ |-> ( n .x. X ) ) e. Fin /\ B e. Fin ) -> ( ( # ` ran ( n e. ZZ |-> ( n .x. X ) ) ) = ( # ` B ) <-> ran ( n e. ZZ |-> ( n .x. X ) ) ~~ B ) ) | 
						
							| 16 | 14 6 15 | syl2anc |  |-  ( ( ( G e. Grp /\ B e. Fin ) /\ X e. B ) -> ( ( # ` ran ( n e. ZZ |-> ( n .x. X ) ) ) = ( # ` B ) <-> ran ( n e. ZZ |-> ( n .x. X ) ) ~~ B ) ) | 
						
							| 17 |  | eqid |  |-  ( n e. ZZ |-> ( n .x. X ) ) = ( n e. ZZ |-> ( n .x. X ) ) | 
						
							| 18 | 1 4 2 17 | dfod2 |  |-  ( ( G e. Grp /\ X e. B ) -> ( O ` X ) = if ( ran ( n e. ZZ |-> ( n .x. X ) ) e. Fin , ( # ` ran ( n e. ZZ |-> ( n .x. X ) ) ) , 0 ) ) | 
						
							| 19 | 18 | adantlr |  |-  ( ( ( G e. Grp /\ B e. Fin ) /\ X e. B ) -> ( O ` X ) = if ( ran ( n e. ZZ |-> ( n .x. X ) ) e. Fin , ( # ` ran ( n e. ZZ |-> ( n .x. X ) ) ) , 0 ) ) | 
						
							| 20 | 14 | iftrued |  |-  ( ( ( G e. Grp /\ B e. Fin ) /\ X e. B ) -> if ( ran ( n e. ZZ |-> ( n .x. X ) ) e. Fin , ( # ` ran ( n e. ZZ |-> ( n .x. X ) ) ) , 0 ) = ( # ` ran ( n e. ZZ |-> ( n .x. X ) ) ) ) | 
						
							| 21 | 19 20 | eqtr2d |  |-  ( ( ( G e. Grp /\ B e. Fin ) /\ X e. B ) -> ( # ` ran ( n e. ZZ |-> ( n .x. X ) ) ) = ( O ` X ) ) | 
						
							| 22 | 21 | eqeq1d |  |-  ( ( ( G e. Grp /\ B e. Fin ) /\ X e. B ) -> ( ( # ` ran ( n e. ZZ |-> ( n .x. X ) ) ) = ( # ` B ) <-> ( O ` X ) = ( # ` B ) ) ) | 
						
							| 23 |  | fisseneq |  |-  ( ( B e. Fin /\ ran ( n e. ZZ |-> ( n .x. X ) ) C_ B /\ ran ( n e. ZZ |-> ( n .x. X ) ) ~~ B ) -> ran ( n e. ZZ |-> ( n .x. X ) ) = B ) | 
						
							| 24 | 23 | 3expia |  |-  ( ( B e. Fin /\ ran ( n e. ZZ |-> ( n .x. X ) ) C_ B ) -> ( ran ( n e. ZZ |-> ( n .x. X ) ) ~~ B -> ran ( n e. ZZ |-> ( n .x. X ) ) = B ) ) | 
						
							| 25 |  | enrefg |  |-  ( B e. Fin -> B ~~ B ) | 
						
							| 26 | 25 | adantr |  |-  ( ( B e. Fin /\ ran ( n e. ZZ |-> ( n .x. X ) ) C_ B ) -> B ~~ B ) | 
						
							| 27 |  | breq1 |  |-  ( ran ( n e. ZZ |-> ( n .x. X ) ) = B -> ( ran ( n e. ZZ |-> ( n .x. X ) ) ~~ B <-> B ~~ B ) ) | 
						
							| 28 | 26 27 | syl5ibrcom |  |-  ( ( B e. Fin /\ ran ( n e. ZZ |-> ( n .x. X ) ) C_ B ) -> ( ran ( n e. ZZ |-> ( n .x. X ) ) = B -> ran ( n e. ZZ |-> ( n .x. X ) ) ~~ B ) ) | 
						
							| 29 | 24 28 | impbid |  |-  ( ( B e. Fin /\ ran ( n e. ZZ |-> ( n .x. X ) ) C_ B ) -> ( ran ( n e. ZZ |-> ( n .x. X ) ) ~~ B <-> ran ( n e. ZZ |-> ( n .x. X ) ) = B ) ) | 
						
							| 30 | 6 13 29 | syl2anc |  |-  ( ( ( G e. Grp /\ B e. Fin ) /\ X e. B ) -> ( ran ( n e. ZZ |-> ( n .x. X ) ) ~~ B <-> ran ( n e. ZZ |-> ( n .x. X ) ) = B ) ) | 
						
							| 31 | 16 22 30 | 3bitr3rd |  |-  ( ( ( G e. Grp /\ B e. Fin ) /\ X e. B ) -> ( ran ( n e. ZZ |-> ( n .x. X ) ) = B <-> ( O ` X ) = ( # ` B ) ) ) | 
						
							| 32 | 31 | pm5.32da |  |-  ( ( G e. Grp /\ B e. Fin ) -> ( ( X e. B /\ ran ( n e. ZZ |-> ( n .x. X ) ) = B ) <-> ( X e. B /\ ( O ` X ) = ( # ` B ) ) ) ) | 
						
							| 33 | 5 32 | bitrid |  |-  ( ( G e. Grp /\ B e. Fin ) -> ( X e. E <-> ( X e. B /\ ( O ` X ) = ( # ` B ) ) ) ) |