| Step | Hyp | Ref | Expression | 
						
							| 1 |  | mdslmd.1 |  |-  A e. CH | 
						
							| 2 |  | mdslmd.2 |  |-  B e. CH | 
						
							| 3 |  | mdslmd.3 |  |-  C e. CH | 
						
							| 4 |  | mdslmd.4 |  |-  D e. CH | 
						
							| 5 |  | chlej2 |  |-  ( ( ( D e. CH /\ A e. CH /\ x e. CH ) /\ D C_ A ) -> ( x vH D ) C_ ( x vH A ) ) | 
						
							| 6 | 5 | ex |  |-  ( ( D e. CH /\ A e. CH /\ x e. CH ) -> ( D C_ A -> ( x vH D ) C_ ( x vH A ) ) ) | 
						
							| 7 | 4 1 6 | mp3an12 |  |-  ( x e. CH -> ( D C_ A -> ( x vH D ) C_ ( x vH A ) ) ) | 
						
							| 8 | 7 | impcom |  |-  ( ( D C_ A /\ x e. CH ) -> ( x vH D ) C_ ( x vH A ) ) | 
						
							| 9 | 8 | ssrind |  |-  ( ( D C_ A /\ x e. CH ) -> ( ( x vH D ) i^i ( B i^i C ) ) C_ ( ( x vH A ) i^i ( B i^i C ) ) ) | 
						
							| 10 | 9 | adantll |  |-  ( ( ( ( A i^i C ) C_ D /\ D C_ A ) /\ x e. CH ) -> ( ( x vH D ) i^i ( B i^i C ) ) C_ ( ( x vH A ) i^i ( B i^i C ) ) ) | 
						
							| 11 | 10 | adantll |  |-  ( ( ( ( A MH B /\ ( A i^i B ) MH C ) /\ ( ( A i^i C ) C_ D /\ D C_ A ) ) /\ x e. CH ) -> ( ( x vH D ) i^i ( B i^i C ) ) C_ ( ( x vH A ) i^i ( B i^i C ) ) ) | 
						
							| 12 | 11 | adantr |  |-  ( ( ( ( ( A MH B /\ ( A i^i B ) MH C ) /\ ( ( A i^i C ) C_ D /\ D C_ A ) ) /\ x e. CH ) /\ x C_ ( B i^i C ) ) -> ( ( x vH D ) i^i ( B i^i C ) ) C_ ( ( x vH A ) i^i ( B i^i C ) ) ) | 
						
							| 13 |  | ssin |  |-  ( ( x C_ B /\ x C_ C ) <-> x C_ ( B i^i C ) ) | 
						
							| 14 |  | inass |  |-  ( ( ( x vH A ) i^i B ) i^i C ) = ( ( x vH A ) i^i ( B i^i C ) ) | 
						
							| 15 |  | mdi |  |-  ( ( ( A e. CH /\ B e. CH /\ x e. CH ) /\ ( A MH B /\ x C_ B ) ) -> ( ( x vH A ) i^i B ) = ( x vH ( A i^i B ) ) ) | 
						
							| 16 | 1 15 | mp3anl1 |  |-  ( ( ( B e. CH /\ x e. CH ) /\ ( A MH B /\ x C_ B ) ) -> ( ( x vH A ) i^i B ) = ( x vH ( A i^i B ) ) ) | 
						
							| 17 | 2 16 | mpanl1 |  |-  ( ( x e. CH /\ ( A MH B /\ x C_ B ) ) -> ( ( x vH A ) i^i B ) = ( x vH ( A i^i B ) ) ) | 
						
							| 18 | 17 | ineq1d |  |-  ( ( x e. CH /\ ( A MH B /\ x C_ B ) ) -> ( ( ( x vH A ) i^i B ) i^i C ) = ( ( x vH ( A i^i B ) ) i^i C ) ) | 
						
							| 19 | 14 18 | eqtr3id |  |-  ( ( x e. CH /\ ( A MH B /\ x C_ B ) ) -> ( ( x vH A ) i^i ( B i^i C ) ) = ( ( x vH ( A i^i B ) ) i^i C ) ) | 
						
							| 20 | 19 | adantrlr |  |-  ( ( x e. CH /\ ( ( A MH B /\ ( A i^i B ) MH C ) /\ x C_ B ) ) -> ( ( x vH A ) i^i ( B i^i C ) ) = ( ( x vH ( A i^i B ) ) i^i C ) ) | 
						
							| 21 | 20 | adantrrr |  |-  ( ( x e. CH /\ ( ( A MH B /\ ( A i^i B ) MH C ) /\ ( x C_ B /\ x C_ C ) ) ) -> ( ( x vH A ) i^i ( B i^i C ) ) = ( ( x vH ( A i^i B ) ) i^i C ) ) | 
						
							| 22 | 1 2 | chincli |  |-  ( A i^i B ) e. CH | 
						
							| 23 |  | mdi |  |-  ( ( ( ( A i^i B ) e. CH /\ C e. CH /\ x e. CH ) /\ ( ( A i^i B ) MH C /\ x C_ C ) ) -> ( ( x vH ( A i^i B ) ) i^i C ) = ( x vH ( ( A i^i B ) i^i C ) ) ) | 
						
							| 24 | 22 23 | mp3anl1 |  |-  ( ( ( C e. CH /\ x e. CH ) /\ ( ( A i^i B ) MH C /\ x C_ C ) ) -> ( ( x vH ( A i^i B ) ) i^i C ) = ( x vH ( ( A i^i B ) i^i C ) ) ) | 
						
							| 25 | 3 24 | mpanl1 |  |-  ( ( x e. CH /\ ( ( A i^i B ) MH C /\ x C_ C ) ) -> ( ( x vH ( A i^i B ) ) i^i C ) = ( x vH ( ( A i^i B ) i^i C ) ) ) | 
						
							| 26 |  | inass |  |-  ( ( A i^i B ) i^i C ) = ( A i^i ( B i^i C ) ) | 
						
							| 27 | 26 | oveq2i |  |-  ( x vH ( ( A i^i B ) i^i C ) ) = ( x vH ( A i^i ( B i^i C ) ) ) | 
						
							| 28 | 25 27 | eqtrdi |  |-  ( ( x e. CH /\ ( ( A i^i B ) MH C /\ x C_ C ) ) -> ( ( x vH ( A i^i B ) ) i^i C ) = ( x vH ( A i^i ( B i^i C ) ) ) ) | 
						
							| 29 | 28 | adantrll |  |-  ( ( x e. CH /\ ( ( A MH B /\ ( A i^i B ) MH C ) /\ x C_ C ) ) -> ( ( x vH ( A i^i B ) ) i^i C ) = ( x vH ( A i^i ( B i^i C ) ) ) ) | 
						
							| 30 | 29 | adantrrl |  |-  ( ( x e. CH /\ ( ( A MH B /\ ( A i^i B ) MH C ) /\ ( x C_ B /\ x C_ C ) ) ) -> ( ( x vH ( A i^i B ) ) i^i C ) = ( x vH ( A i^i ( B i^i C ) ) ) ) | 
						
							| 31 | 21 30 | eqtrd |  |-  ( ( x e. CH /\ ( ( A MH B /\ ( A i^i B ) MH C ) /\ ( x C_ B /\ x C_ C ) ) ) -> ( ( x vH A ) i^i ( B i^i C ) ) = ( x vH ( A i^i ( B i^i C ) ) ) ) | 
						
							| 32 | 31 | ancoms |  |-  ( ( ( ( A MH B /\ ( A i^i B ) MH C ) /\ ( x C_ B /\ x C_ C ) ) /\ x e. CH ) -> ( ( x vH A ) i^i ( B i^i C ) ) = ( x vH ( A i^i ( B i^i C ) ) ) ) | 
						
							| 33 | 32 | an32s |  |-  ( ( ( ( A MH B /\ ( A i^i B ) MH C ) /\ x e. CH ) /\ ( x C_ B /\ x C_ C ) ) -> ( ( x vH A ) i^i ( B i^i C ) ) = ( x vH ( A i^i ( B i^i C ) ) ) ) | 
						
							| 34 | 13 33 | sylan2br |  |-  ( ( ( ( A MH B /\ ( A i^i B ) MH C ) /\ x e. CH ) /\ x C_ ( B i^i C ) ) -> ( ( x vH A ) i^i ( B i^i C ) ) = ( x vH ( A i^i ( B i^i C ) ) ) ) | 
						
							| 35 | 34 | adantllr |  |-  ( ( ( ( ( A MH B /\ ( A i^i B ) MH C ) /\ ( ( A i^i C ) C_ D /\ D C_ A ) ) /\ x e. CH ) /\ x C_ ( B i^i C ) ) -> ( ( x vH A ) i^i ( B i^i C ) ) = ( x vH ( A i^i ( B i^i C ) ) ) ) | 
						
							| 36 |  | inass |  |-  ( ( A i^i C ) i^i ( B i^i C ) ) = ( A i^i ( C i^i ( B i^i C ) ) ) | 
						
							| 37 |  | in12 |  |-  ( C i^i ( B i^i C ) ) = ( B i^i ( C i^i C ) ) | 
						
							| 38 |  | inidm |  |-  ( C i^i C ) = C | 
						
							| 39 | 38 | ineq2i |  |-  ( B i^i ( C i^i C ) ) = ( B i^i C ) | 
						
							| 40 | 37 39 | eqtri |  |-  ( C i^i ( B i^i C ) ) = ( B i^i C ) | 
						
							| 41 | 40 | ineq2i |  |-  ( A i^i ( C i^i ( B i^i C ) ) ) = ( A i^i ( B i^i C ) ) | 
						
							| 42 | 36 41 | eqtr2i |  |-  ( A i^i ( B i^i C ) ) = ( ( A i^i C ) i^i ( B i^i C ) ) | 
						
							| 43 |  | ssrin |  |-  ( ( A i^i C ) C_ D -> ( ( A i^i C ) i^i ( B i^i C ) ) C_ ( D i^i ( B i^i C ) ) ) | 
						
							| 44 | 42 43 | eqsstrid |  |-  ( ( A i^i C ) C_ D -> ( A i^i ( B i^i C ) ) C_ ( D i^i ( B i^i C ) ) ) | 
						
							| 45 |  | ssrin |  |-  ( D C_ A -> ( D i^i ( B i^i C ) ) C_ ( A i^i ( B i^i C ) ) ) | 
						
							| 46 | 44 45 | anim12i |  |-  ( ( ( A i^i C ) C_ D /\ D C_ A ) -> ( ( A i^i ( B i^i C ) ) C_ ( D i^i ( B i^i C ) ) /\ ( D i^i ( B i^i C ) ) C_ ( A i^i ( B i^i C ) ) ) ) | 
						
							| 47 |  | eqss |  |-  ( ( A i^i ( B i^i C ) ) = ( D i^i ( B i^i C ) ) <-> ( ( A i^i ( B i^i C ) ) C_ ( D i^i ( B i^i C ) ) /\ ( D i^i ( B i^i C ) ) C_ ( A i^i ( B i^i C ) ) ) ) | 
						
							| 48 | 46 47 | sylibr |  |-  ( ( ( A i^i C ) C_ D /\ D C_ A ) -> ( A i^i ( B i^i C ) ) = ( D i^i ( B i^i C ) ) ) | 
						
							| 49 | 48 | oveq2d |  |-  ( ( ( A i^i C ) C_ D /\ D C_ A ) -> ( x vH ( A i^i ( B i^i C ) ) ) = ( x vH ( D i^i ( B i^i C ) ) ) ) | 
						
							| 50 | 49 | ad3antlr |  |-  ( ( ( ( ( A MH B /\ ( A i^i B ) MH C ) /\ ( ( A i^i C ) C_ D /\ D C_ A ) ) /\ x e. CH ) /\ x C_ ( B i^i C ) ) -> ( x vH ( A i^i ( B i^i C ) ) ) = ( x vH ( D i^i ( B i^i C ) ) ) ) | 
						
							| 51 | 35 50 | eqtrd |  |-  ( ( ( ( ( A MH B /\ ( A i^i B ) MH C ) /\ ( ( A i^i C ) C_ D /\ D C_ A ) ) /\ x e. CH ) /\ x C_ ( B i^i C ) ) -> ( ( x vH A ) i^i ( B i^i C ) ) = ( x vH ( D i^i ( B i^i C ) ) ) ) | 
						
							| 52 | 12 51 | sseqtrd |  |-  ( ( ( ( ( A MH B /\ ( A i^i B ) MH C ) /\ ( ( A i^i C ) C_ D /\ D C_ A ) ) /\ x e. CH ) /\ x C_ ( B i^i C ) ) -> ( ( x vH D ) i^i ( B i^i C ) ) C_ ( x vH ( D i^i ( B i^i C ) ) ) ) | 
						
							| 53 | 52 | ex |  |-  ( ( ( ( A MH B /\ ( A i^i B ) MH C ) /\ ( ( A i^i C ) C_ D /\ D C_ A ) ) /\ x e. CH ) -> ( x C_ ( B i^i C ) -> ( ( x vH D ) i^i ( B i^i C ) ) C_ ( x vH ( D i^i ( B i^i C ) ) ) ) ) | 
						
							| 54 | 53 | ralrimiva |  |-  ( ( ( A MH B /\ ( A i^i B ) MH C ) /\ ( ( A i^i C ) C_ D /\ D C_ A ) ) -> A. x e. CH ( x C_ ( B i^i C ) -> ( ( x vH D ) i^i ( B i^i C ) ) C_ ( x vH ( D i^i ( B i^i C ) ) ) ) ) | 
						
							| 55 | 2 3 | chincli |  |-  ( B i^i C ) e. CH | 
						
							| 56 |  | mdbr2 |  |-  ( ( D e. CH /\ ( B i^i C ) e. CH ) -> ( D MH ( B i^i C ) <-> A. x e. CH ( x C_ ( B i^i C ) -> ( ( x vH D ) i^i ( B i^i C ) ) C_ ( x vH ( D i^i ( B i^i C ) ) ) ) ) ) | 
						
							| 57 | 4 55 56 | mp2an |  |-  ( D MH ( B i^i C ) <-> A. x e. CH ( x C_ ( B i^i C ) -> ( ( x vH D ) i^i ( B i^i C ) ) C_ ( x vH ( D i^i ( B i^i C ) ) ) ) ) | 
						
							| 58 | 54 57 | sylibr |  |-  ( ( ( A MH B /\ ( A i^i B ) MH C ) /\ ( ( A i^i C ) C_ D /\ D C_ A ) ) -> D MH ( B i^i C ) ) |