| Step | Hyp | Ref | Expression | 
						
							| 1 |  | mdsymlem1.1 |  | 
						
							| 2 |  | mdsymlem1.2 |  | 
						
							| 3 |  | mdsymlem1.3 |  | 
						
							| 4 |  | chub2 |  | 
						
							| 5 | 1 4 | mpan2 |  | 
						
							| 6 | 5 3 | sseqtrrdi |  | 
						
							| 7 | 1 2 | chjcomi |  | 
						
							| 8 | 7 | sseq2i |  | 
						
							| 9 | 8 | biimpi |  | 
						
							| 10 | 6 9 | anim12i |  | 
						
							| 11 |  | ssin |  | 
						
							| 12 | 10 11 | sylib |  | 
						
							| 13 | 12 | ad2ant2rl |  | 
						
							| 14 |  | chjcl |  | 
						
							| 15 | 1 14 | mpan |  | 
						
							| 16 | 3 15 | eqeltrid |  | 
						
							| 17 | 16 | adantr |  | 
						
							| 18 |  | chub1 |  | 
						
							| 19 | 1 18 | mpan |  | 
						
							| 20 | 19 3 | sseqtrrdi |  | 
						
							| 21 | 20 | anim2i |  | 
						
							| 22 | 21 | ancoms |  | 
						
							| 23 |  | dmdi |  | 
						
							| 24 | 2 23 | mp3anl1 |  | 
						
							| 25 | 1 24 | mpanl1 |  | 
						
							| 26 | 17 22 25 | syl2anc |  | 
						
							| 27 | 26 | adantlr |  | 
						
							| 28 |  | incom |  | 
						
							| 29 | 28 | oveq1i |  | 
						
							| 30 |  | chincl |  | 
						
							| 31 | 2 30 | mpan |  | 
						
							| 32 |  | chlejb1 |  | 
						
							| 33 | 1 32 | mpan2 |  | 
						
							| 34 | 16 31 33 | 3syl |  | 
						
							| 35 | 34 | biimpa |  | 
						
							| 36 | 29 35 | eqtrid |  | 
						
							| 37 | 36 | adantr |  | 
						
							| 38 | 27 37 | eqtr3d |  | 
						
							| 39 | 38 | adantrr |  | 
						
							| 40 | 13 39 | sseqtrd |  |