| Step | Hyp | Ref | Expression | 
						
							| 1 |  | ringnegl.b |  | 
						
							| 2 |  | ringnegl.t |  | 
						
							| 3 |  | ringnegl.u |  | 
						
							| 4 |  | ringnegl.n |  | 
						
							| 5 |  | ringnegl.r |  | 
						
							| 6 |  | ringnegl.x |  | 
						
							| 7 | 1 3 | ringidcl |  | 
						
							| 8 | 5 7 | syl |  | 
						
							| 9 |  | ringgrp |  | 
						
							| 10 | 5 9 | syl |  | 
						
							| 11 | 1 4 | grpinvcl |  | 
						
							| 12 | 10 8 11 | syl2anc |  | 
						
							| 13 |  | eqid |  | 
						
							| 14 | 1 13 2 | ringdir |  | 
						
							| 15 | 5 8 12 6 14 | syl13anc |  | 
						
							| 16 |  | eqid |  | 
						
							| 17 | 1 13 16 4 | grprinv |  | 
						
							| 18 | 10 8 17 | syl2anc |  | 
						
							| 19 | 18 | oveq1d |  | 
						
							| 20 | 1 2 16 | ringlz |  | 
						
							| 21 | 5 6 20 | syl2anc |  | 
						
							| 22 | 19 21 | eqtrd |  | 
						
							| 23 | 1 2 3 | ringlidm |  | 
						
							| 24 | 5 6 23 | syl2anc |  | 
						
							| 25 | 24 | oveq1d |  | 
						
							| 26 | 15 22 25 | 3eqtr3rd |  | 
						
							| 27 | 1 2 | ringcl |  | 
						
							| 28 | 5 12 6 27 | syl3anc |  | 
						
							| 29 | 1 13 16 4 | grpinvid1 |  | 
						
							| 30 | 10 6 28 29 | syl3anc |  | 
						
							| 31 | 26 30 | mpbird |  | 
						
							| 32 | 31 | eqcomd |  |