| Step | Hyp | Ref | Expression | 
						
							| 1 |  | issubrgd.s |  | 
						
							| 2 |  | issubrgd.z |  | 
						
							| 3 |  | issubrgd.p |  | 
						
							| 4 |  | issubrgd.ss |  | 
						
							| 5 |  | issubrgd.zcl |  | 
						
							| 6 |  | issubrgd.acl |  | 
						
							| 7 |  | issubrgd.ncl |  | 
						
							| 8 |  | issubrgd.o |  | 
						
							| 9 |  | issubrgd.t |  | 
						
							| 10 |  | issubrgd.ocl |  | 
						
							| 11 |  | issubrgd.tcl |  | 
						
							| 12 |  | issubrgd.g |  | 
						
							| 13 |  | ringgrp |  | 
						
							| 14 | 12 13 | syl |  | 
						
							| 15 | 1 2 3 4 5 6 7 14 | issubgrpd2 |  | 
						
							| 16 | 8 10 | eqeltrrd |  | 
						
							| 17 | 9 | oveqdr |  | 
						
							| 18 | 11 | 3expb |  | 
						
							| 19 | 17 18 | eqeltrrd |  | 
						
							| 20 | 19 | ralrimivva |  | 
						
							| 21 |  | eqid |  | 
						
							| 22 |  | eqid |  | 
						
							| 23 |  | eqid |  | 
						
							| 24 | 21 22 23 | issubrg2 |  | 
						
							| 25 | 12 24 | syl |  | 
						
							| 26 | 15 16 20 25 | mpbir3and |  |