| Step | Hyp | Ref | Expression | 
						
							| 1 |  | ablsubsub23.v |  | 
						
							| 2 |  | ablsubsub23.m |  | 
						
							| 3 |  | simpl |  | 
						
							| 4 |  | simpr3 |  | 
						
							| 5 |  | simpr2 |  | 
						
							| 6 |  | eqid |  | 
						
							| 7 | 1 6 | ablcom |  | 
						
							| 8 | 3 4 5 7 | syl3anc |  | 
						
							| 9 | 8 | eqeq1d |  | 
						
							| 10 |  | ablgrp |  | 
						
							| 11 | 1 6 2 | grpsubadd |  | 
						
							| 12 | 10 11 | sylan |  | 
						
							| 13 |  | 3ancomb |  | 
						
							| 14 | 13 | biimpi |  | 
						
							| 15 | 1 6 2 | grpsubadd |  | 
						
							| 16 | 10 14 15 | syl2an |  | 
						
							| 17 | 9 12 16 | 3bitr4d |  |