| Step | Hyp | Ref | Expression | 
						
							| 1 |  | nmmul.x |  | 
						
							| 2 |  | nmmul.n |  | 
						
							| 3 |  | nmmul.t |  | 
						
							| 4 |  | nrgdsdi.d |  | 
						
							| 5 |  | simpl |  | 
						
							| 6 |  | nrgring |  | 
						
							| 7 | 6 | adantr |  | 
						
							| 8 |  | ringgrp |  | 
						
							| 9 | 7 8 | syl |  | 
						
							| 10 |  | simpr1 |  | 
						
							| 11 |  | simpr2 |  | 
						
							| 12 |  | eqid |  | 
						
							| 13 | 1 12 | grpsubcl |  | 
						
							| 14 | 9 10 11 13 | syl3anc |  | 
						
							| 15 |  | simpr3 |  | 
						
							| 16 | 1 2 3 | nmmul |  | 
						
							| 17 | 5 14 15 16 | syl3anc |  | 
						
							| 18 | 1 3 12 7 10 11 15 | ringsubdir |  | 
						
							| 19 | 18 | fveq2d |  | 
						
							| 20 | 17 19 | eqtr3d |  | 
						
							| 21 |  | nrgngp |  | 
						
							| 22 | 21 | adantr |  | 
						
							| 23 | 2 1 12 4 | ngpds |  | 
						
							| 24 | 22 10 11 23 | syl3anc |  | 
						
							| 25 | 24 | oveq1d |  | 
						
							| 26 | 1 3 | ringcl |  | 
						
							| 27 | 7 10 15 26 | syl3anc |  | 
						
							| 28 | 1 3 | ringcl |  | 
						
							| 29 | 7 11 15 28 | syl3anc |  | 
						
							| 30 | 2 1 12 4 | ngpds |  | 
						
							| 31 | 22 27 29 30 | syl3anc |  | 
						
							| 32 | 20 25 31 | 3eqtr4d |  |