| Step | Hyp | Ref | Expression | 
						
							| 1 |  | mdsymlem1.1 |  |-  A e. CH | 
						
							| 2 |  | mdsymlem1.2 |  |-  B e. CH | 
						
							| 3 |  | mdsymlem1.3 |  |-  C = ( A vH p ) | 
						
							| 4 | 1 2 3 | mdsymlem2 |  |-  ( ( ( p e. HAtoms /\ ( B i^i C ) C_ A ) /\ ( B MH* A /\ p C_ ( A vH B ) ) ) -> ( B =/= 0H -> E. r e. HAtoms E. q e. HAtoms ( p C_ ( q vH r ) /\ ( q C_ A /\ r C_ B ) ) ) ) | 
						
							| 5 | 4 | exp31 |  |-  ( p e. HAtoms -> ( ( B i^i C ) C_ A -> ( ( B MH* A /\ p C_ ( A vH B ) ) -> ( B =/= 0H -> E. r e. HAtoms E. q e. HAtoms ( p C_ ( q vH r ) /\ ( q C_ A /\ r C_ B ) ) ) ) ) ) | 
						
							| 6 | 5 | com4t |  |-  ( ( B MH* A /\ p C_ ( A vH B ) ) -> ( B =/= 0H -> ( p e. HAtoms -> ( ( B i^i C ) C_ A -> E. r e. HAtoms E. q e. HAtoms ( p C_ ( q vH r ) /\ ( q C_ A /\ r C_ B ) ) ) ) ) ) | 
						
							| 7 | 6 | ex |  |-  ( B MH* A -> ( p C_ ( A vH B ) -> ( B =/= 0H -> ( p e. HAtoms -> ( ( B i^i C ) C_ A -> E. r e. HAtoms E. q e. HAtoms ( p C_ ( q vH r ) /\ ( q C_ A /\ r C_ B ) ) ) ) ) ) ) | 
						
							| 8 | 7 | com23 |  |-  ( B MH* A -> ( B =/= 0H -> ( p C_ ( A vH B ) -> ( p e. HAtoms -> ( ( B i^i C ) C_ A -> E. r e. HAtoms E. q e. HAtoms ( p C_ ( q vH r ) /\ ( q C_ A /\ r C_ B ) ) ) ) ) ) ) | 
						
							| 9 | 8 | a1d |  |-  ( B MH* A -> ( A =/= 0H -> ( B =/= 0H -> ( p C_ ( A vH B ) -> ( p e. HAtoms -> ( ( B i^i C ) C_ A -> E. r e. HAtoms E. q e. HAtoms ( p C_ ( q vH r ) /\ ( q C_ A /\ r C_ B ) ) ) ) ) ) ) ) | 
						
							| 10 | 9 | imp44 |  |-  ( ( B MH* A /\ ( ( A =/= 0H /\ B =/= 0H ) /\ p C_ ( A vH B ) ) ) -> ( p e. HAtoms -> ( ( B i^i C ) C_ A -> E. r e. HAtoms E. q e. HAtoms ( p C_ ( q vH r ) /\ ( q C_ A /\ r C_ B ) ) ) ) ) | 
						
							| 11 | 10 | com3l |  |-  ( p e. HAtoms -> ( ( B i^i C ) C_ A -> ( ( B MH* A /\ ( ( A =/= 0H /\ B =/= 0H ) /\ p C_ ( A vH B ) ) ) -> E. r e. HAtoms E. q e. HAtoms ( p C_ ( q vH r ) /\ ( q C_ A /\ r C_ B ) ) ) ) ) | 
						
							| 12 | 1 2 3 | mdsymlem3 |  |-  ( ( ( ( p e. HAtoms /\ -. ( B i^i C ) C_ A ) /\ p C_ ( A vH B ) ) /\ A =/= 0H ) -> E. r e. HAtoms E. q e. HAtoms ( p C_ ( q vH r ) /\ ( q C_ A /\ r C_ B ) ) ) | 
						
							| 13 | 12 | anasss |  |-  ( ( ( p e. HAtoms /\ -. ( B i^i C ) C_ A ) /\ ( p C_ ( A vH B ) /\ A =/= 0H ) ) -> E. r e. HAtoms E. q e. HAtoms ( p C_ ( q vH r ) /\ ( q C_ A /\ r C_ B ) ) ) | 
						
							| 14 | 13 | exp31 |  |-  ( p e. HAtoms -> ( -. ( B i^i C ) C_ A -> ( ( p C_ ( A vH B ) /\ A =/= 0H ) -> E. r e. HAtoms E. q e. HAtoms ( p C_ ( q vH r ) /\ ( q C_ A /\ r C_ B ) ) ) ) ) | 
						
							| 15 | 14 | com3r |  |-  ( ( p C_ ( A vH B ) /\ A =/= 0H ) -> ( p e. HAtoms -> ( -. ( B i^i C ) C_ A -> E. r e. HAtoms E. q e. HAtoms ( p C_ ( q vH r ) /\ ( q C_ A /\ r C_ B ) ) ) ) ) | 
						
							| 16 | 15 | ancoms |  |-  ( ( A =/= 0H /\ p C_ ( A vH B ) ) -> ( p e. HAtoms -> ( -. ( B i^i C ) C_ A -> E. r e. HAtoms E. q e. HAtoms ( p C_ ( q vH r ) /\ ( q C_ A /\ r C_ B ) ) ) ) ) | 
						
							| 17 | 16 | adantlr |  |-  ( ( ( A =/= 0H /\ B =/= 0H ) /\ p C_ ( A vH B ) ) -> ( p e. HAtoms -> ( -. ( B i^i C ) C_ A -> E. r e. HAtoms E. q e. HAtoms ( p C_ ( q vH r ) /\ ( q C_ A /\ r C_ B ) ) ) ) ) | 
						
							| 18 | 17 | adantl |  |-  ( ( B MH* A /\ ( ( A =/= 0H /\ B =/= 0H ) /\ p C_ ( A vH B ) ) ) -> ( p e. HAtoms -> ( -. ( B i^i C ) C_ A -> E. r e. HAtoms E. q e. HAtoms ( p C_ ( q vH r ) /\ ( q C_ A /\ r C_ B ) ) ) ) ) | 
						
							| 19 | 18 | com3l |  |-  ( p e. HAtoms -> ( -. ( B i^i C ) C_ A -> ( ( B MH* A /\ ( ( A =/= 0H /\ B =/= 0H ) /\ p C_ ( A vH B ) ) ) -> E. r e. HAtoms E. q e. HAtoms ( p C_ ( q vH r ) /\ ( q C_ A /\ r C_ B ) ) ) ) ) | 
						
							| 20 | 11 19 | pm2.61d |  |-  ( p e. HAtoms -> ( ( B MH* A /\ ( ( A =/= 0H /\ B =/= 0H ) /\ p C_ ( A vH B ) ) ) -> E. r e. HAtoms E. q e. HAtoms ( p C_ ( q vH r ) /\ ( q C_ A /\ r C_ B ) ) ) ) | 
						
							| 21 |  | rexcom |  |-  ( E. r e. HAtoms E. q e. HAtoms ( p C_ ( q vH r ) /\ ( q C_ A /\ r C_ B ) ) <-> E. q e. HAtoms E. r e. HAtoms ( p C_ ( q vH r ) /\ ( q C_ A /\ r C_ B ) ) ) | 
						
							| 22 | 20 21 | imbitrdi |  |-  ( p e. HAtoms -> ( ( B MH* A /\ ( ( A =/= 0H /\ B =/= 0H ) /\ p C_ ( A vH B ) ) ) -> E. q e. HAtoms E. r e. HAtoms ( p C_ ( q vH r ) /\ ( q C_ A /\ r C_ B ) ) ) ) |