| Step | Hyp | Ref | Expression | 
						
							| 1 |  | mdsymlem1.1 |  | 
						
							| 2 |  | mdsymlem1.2 |  | 
						
							| 3 |  | mdsymlem1.3 |  | 
						
							| 4 | 1 2 3 | mdsymlem2 |  | 
						
							| 5 | 4 | exp31 |  | 
						
							| 6 | 5 | com4t |  | 
						
							| 7 | 6 | ex |  | 
						
							| 8 | 7 | com23 |  | 
						
							| 9 | 8 | a1d |  | 
						
							| 10 | 9 | imp44 |  | 
						
							| 11 | 10 | com3l |  | 
						
							| 12 | 1 2 3 | mdsymlem3 |  | 
						
							| 13 | 12 | anasss |  | 
						
							| 14 | 13 | exp31 |  | 
						
							| 15 | 14 | com3r |  | 
						
							| 16 | 15 | ancoms |  | 
						
							| 17 | 16 | adantlr |  | 
						
							| 18 | 17 | adantl |  | 
						
							| 19 | 18 | com3l |  | 
						
							| 20 | 11 19 | pm2.61d |  | 
						
							| 21 |  | rexcom |  | 
						
							| 22 | 20 21 | imbitrdi |  |