| Step | Hyp | Ref | Expression | 
						
							| 1 |  | finodsubmsubg.o |  |-  O = ( od ` G ) | 
						
							| 2 |  | finodsubmsubg.g |  |-  ( ph -> G e. Grp ) | 
						
							| 3 |  | finodsubmsubg.s |  |-  ( ph -> S e. ( SubMnd ` G ) ) | 
						
							| 4 |  | finodsubmsubg.1 |  |-  ( ph -> A. a e. S ( O ` a ) e. NN ) | 
						
							| 5 |  | eqid |  |-  ( Base ` G ) = ( Base ` G ) | 
						
							| 6 |  | eqid |  |-  ( .g ` G ) = ( .g ` G ) | 
						
							| 7 |  | eqid |  |-  ( invg ` G ) = ( invg ` G ) | 
						
							| 8 | 2 | adantr |  |-  ( ( ph /\ a e. S ) -> G e. Grp ) | 
						
							| 9 | 5 | submss |  |-  ( S e. ( SubMnd ` G ) -> S C_ ( Base ` G ) ) | 
						
							| 10 | 3 9 | syl |  |-  ( ph -> S C_ ( Base ` G ) ) | 
						
							| 11 | 10 | sselda |  |-  ( ( ph /\ a e. S ) -> a e. ( Base ` G ) ) | 
						
							| 12 | 5 1 6 7 8 11 | odm1inv |  |-  ( ( ph /\ a e. S ) -> ( ( ( O ` a ) - 1 ) ( .g ` G ) a ) = ( ( invg ` G ) ` a ) ) | 
						
							| 13 | 12 | adantr |  |-  ( ( ( ph /\ a e. S ) /\ ( O ` a ) e. NN ) -> ( ( ( O ` a ) - 1 ) ( .g ` G ) a ) = ( ( invg ` G ) ` a ) ) | 
						
							| 14 |  | eqid |  |-  ( Base ` ( G |`s S ) ) = ( Base ` ( G |`s S ) ) | 
						
							| 15 |  | eqid |  |-  ( .g ` ( G |`s S ) ) = ( .g ` ( G |`s S ) ) | 
						
							| 16 |  | eqid |  |-  ( G |`s S ) = ( G |`s S ) | 
						
							| 17 | 16 | submmnd |  |-  ( S e. ( SubMnd ` G ) -> ( G |`s S ) e. Mnd ) | 
						
							| 18 | 3 17 | syl |  |-  ( ph -> ( G |`s S ) e. Mnd ) | 
						
							| 19 | 18 | ad2antrr |  |-  ( ( ( ph /\ a e. S ) /\ ( O ` a ) e. NN ) -> ( G |`s S ) e. Mnd ) | 
						
							| 20 |  | nnm1nn0 |  |-  ( ( O ` a ) e. NN -> ( ( O ` a ) - 1 ) e. NN0 ) | 
						
							| 21 | 20 | adantl |  |-  ( ( ( ph /\ a e. S ) /\ ( O ` a ) e. NN ) -> ( ( O ` a ) - 1 ) e. NN0 ) | 
						
							| 22 |  | simplr |  |-  ( ( ( ph /\ a e. S ) /\ ( O ` a ) e. NN ) -> a e. S ) | 
						
							| 23 | 16 5 | ressbas2 |  |-  ( S C_ ( Base ` G ) -> S = ( Base ` ( G |`s S ) ) ) | 
						
							| 24 | 10 23 | syl |  |-  ( ph -> S = ( Base ` ( G |`s S ) ) ) | 
						
							| 25 | 24 | ad2antrr |  |-  ( ( ( ph /\ a e. S ) /\ ( O ` a ) e. NN ) -> S = ( Base ` ( G |`s S ) ) ) | 
						
							| 26 | 22 25 | eleqtrd |  |-  ( ( ( ph /\ a e. S ) /\ ( O ` a ) e. NN ) -> a e. ( Base ` ( G |`s S ) ) ) | 
						
							| 27 | 14 15 19 21 26 | mulgnn0cld |  |-  ( ( ( ph /\ a e. S ) /\ ( O ` a ) e. NN ) -> ( ( ( O ` a ) - 1 ) ( .g ` ( G |`s S ) ) a ) e. ( Base ` ( G |`s S ) ) ) | 
						
							| 28 | 3 | ad2antrr |  |-  ( ( ( ph /\ a e. S ) /\ ( O ` a ) e. NN ) -> S e. ( SubMnd ` G ) ) | 
						
							| 29 | 6 16 15 | submmulg |  |-  ( ( S e. ( SubMnd ` G ) /\ ( ( O ` a ) - 1 ) e. NN0 /\ a e. S ) -> ( ( ( O ` a ) - 1 ) ( .g ` G ) a ) = ( ( ( O ` a ) - 1 ) ( .g ` ( G |`s S ) ) a ) ) | 
						
							| 30 | 28 21 22 29 | syl3anc |  |-  ( ( ( ph /\ a e. S ) /\ ( O ` a ) e. NN ) -> ( ( ( O ` a ) - 1 ) ( .g ` G ) a ) = ( ( ( O ` a ) - 1 ) ( .g ` ( G |`s S ) ) a ) ) | 
						
							| 31 | 27 30 25 | 3eltr4d |  |-  ( ( ( ph /\ a e. S ) /\ ( O ` a ) e. NN ) -> ( ( ( O ` a ) - 1 ) ( .g ` G ) a ) e. S ) | 
						
							| 32 | 13 31 | eqeltrrd |  |-  ( ( ( ph /\ a e. S ) /\ ( O ` a ) e. NN ) -> ( ( invg ` G ) ` a ) e. S ) | 
						
							| 33 | 32 | ex |  |-  ( ( ph /\ a e. S ) -> ( ( O ` a ) e. NN -> ( ( invg ` G ) ` a ) e. S ) ) | 
						
							| 34 | 33 | ralimdva |  |-  ( ph -> ( A. a e. S ( O ` a ) e. NN -> A. a e. S ( ( invg ` G ) ` a ) e. S ) ) | 
						
							| 35 | 4 34 | mpd |  |-  ( ph -> A. a e. S ( ( invg ` G ) ` a ) e. S ) | 
						
							| 36 | 7 | issubg3 |  |-  ( G e. Grp -> ( S e. ( SubGrp ` G ) <-> ( S e. ( SubMnd ` G ) /\ A. a e. S ( ( invg ` G ) ` a ) e. S ) ) ) | 
						
							| 37 | 2 36 | syl |  |-  ( ph -> ( S e. ( SubGrp ` G ) <-> ( S e. ( SubMnd ` G ) /\ A. a e. S ( ( invg ` G ) ` a ) e. S ) ) ) | 
						
							| 38 | 3 35 37 | mpbir2and |  |-  ( ph -> S e. ( SubGrp ` G ) ) |