| Step | Hyp | Ref | Expression | 
						
							| 1 |  | pgrpsubgsymgbi.g |  |-  G = ( SymGrp ` A ) | 
						
							| 2 |  | pgrpsubgsymgbi.b |  |-  B = ( Base ` G ) | 
						
							| 3 | 2 | issubg |  |-  ( P e. ( SubGrp ` G ) <-> ( G e. Grp /\ P C_ B /\ ( G |`s P ) e. Grp ) ) | 
						
							| 4 |  | 3anass |  |-  ( ( G e. Grp /\ P C_ B /\ ( G |`s P ) e. Grp ) <-> ( G e. Grp /\ ( P C_ B /\ ( G |`s P ) e. Grp ) ) ) | 
						
							| 5 | 3 4 | bitri |  |-  ( P e. ( SubGrp ` G ) <-> ( G e. Grp /\ ( P C_ B /\ ( G |`s P ) e. Grp ) ) ) | 
						
							| 6 | 1 | symggrp |  |-  ( A e. V -> G e. Grp ) | 
						
							| 7 |  | ibar |  |-  ( G e. Grp -> ( ( P C_ B /\ ( G |`s P ) e. Grp ) <-> ( G e. Grp /\ ( P C_ B /\ ( G |`s P ) e. Grp ) ) ) ) | 
						
							| 8 | 7 | bicomd |  |-  ( G e. Grp -> ( ( G e. Grp /\ ( P C_ B /\ ( G |`s P ) e. Grp ) ) <-> ( P C_ B /\ ( G |`s P ) e. Grp ) ) ) | 
						
							| 9 | 6 8 | syl |  |-  ( A e. V -> ( ( G e. Grp /\ ( P C_ B /\ ( G |`s P ) e. Grp ) ) <-> ( P C_ B /\ ( G |`s P ) e. Grp ) ) ) | 
						
							| 10 | 5 9 | bitrid |  |-  ( A e. V -> ( P e. ( SubGrp ` G ) <-> ( P C_ B /\ ( G |`s P ) e. Grp ) ) ) |