| Step | Hyp | Ref | Expression | 
						
							| 1 |  | pgrpsubgsymgbi.g |  | 
						
							| 2 |  | pgrpsubgsymgbi.b |  | 
						
							| 3 |  | pgrpsubgsymg.c |  | 
						
							| 4 | 1 | symggrp |  | 
						
							| 5 |  | simp1 |  | 
						
							| 6 | 4 5 | anim12i |  | 
						
							| 7 |  | simp2 |  | 
						
							| 8 |  | simp3 |  | 
						
							| 9 | 1 2 | symgbasmap |  | 
						
							| 10 | 9 | ssriv |  | 
						
							| 11 |  | sstr |  | 
						
							| 12 | 10 11 | mpan2 |  | 
						
							| 13 |  | resmpo |  | 
						
							| 14 | 13 | anidms |  | 
						
							| 15 | 12 14 | syl |  | 
						
							| 16 |  | eqid |  | 
						
							| 17 |  | eqid |  | 
						
							| 18 | 1 16 17 | symgplusg |  | 
						
							| 19 | 18 | eqcomi |  | 
						
							| 20 | 19 | reseq1i |  | 
						
							| 21 | 15 20 | eqtr3di |  | 
						
							| 22 | 21 | 3ad2ant2 |  | 
						
							| 23 | 8 22 | eqtrd |  | 
						
							| 24 | 7 23 | jca |  | 
						
							| 25 | 24 | adantl |  | 
						
							| 26 | 2 3 | grpissubg |  | 
						
							| 27 | 6 25 26 | sylc |  | 
						
							| 28 | 27 | ex |  |