| Step | Hyp | Ref | Expression | 
						
							| 1 |  | mdsl.1 |  |-  A e. CH | 
						
							| 2 |  | mdsl.2 |  |-  B e. CH | 
						
							| 3 |  | chub1 |  |-  ( ( x e. CH /\ A e. CH ) -> x C_ ( x vH A ) ) | 
						
							| 4 | 1 3 | mpan2 |  |-  ( x e. CH -> x C_ ( x vH A ) ) | 
						
							| 5 |  | iba |  |-  ( x C_ B -> ( x C_ ( x vH A ) <-> ( x C_ ( x vH A ) /\ x C_ B ) ) ) | 
						
							| 6 |  | ssin |  |-  ( ( x C_ ( x vH A ) /\ x C_ B ) <-> x C_ ( ( x vH A ) i^i B ) ) | 
						
							| 7 | 5 6 | bitrdi |  |-  ( x C_ B -> ( x C_ ( x vH A ) <-> x C_ ( ( x vH A ) i^i B ) ) ) | 
						
							| 8 | 4 7 | syl5ibcom |  |-  ( x e. CH -> ( x C_ B -> x C_ ( ( x vH A ) i^i B ) ) ) | 
						
							| 9 |  | chub2 |  |-  ( ( A e. CH /\ x e. CH ) -> A C_ ( x vH A ) ) | 
						
							| 10 | 1 9 | mpan |  |-  ( x e. CH -> A C_ ( x vH A ) ) | 
						
							| 11 | 10 | ssrind |  |-  ( x e. CH -> ( A i^i B ) C_ ( ( x vH A ) i^i B ) ) | 
						
							| 12 | 8 11 | jctird |  |-  ( x e. CH -> ( x C_ B -> ( x C_ ( ( x vH A ) i^i B ) /\ ( A i^i B ) C_ ( ( x vH A ) i^i B ) ) ) ) | 
						
							| 13 |  | chjcl |  |-  ( ( x e. CH /\ A e. CH ) -> ( x vH A ) e. CH ) | 
						
							| 14 | 1 13 | mpan2 |  |-  ( x e. CH -> ( x vH A ) e. CH ) | 
						
							| 15 |  | chincl |  |-  ( ( ( x vH A ) e. CH /\ B e. CH ) -> ( ( x vH A ) i^i B ) e. CH ) | 
						
							| 16 | 2 15 | mpan2 |  |-  ( ( x vH A ) e. CH -> ( ( x vH A ) i^i B ) e. CH ) | 
						
							| 17 | 14 16 | syl |  |-  ( x e. CH -> ( ( x vH A ) i^i B ) e. CH ) | 
						
							| 18 | 1 2 | chincli |  |-  ( A i^i B ) e. CH | 
						
							| 19 |  | chlub |  |-  ( ( x e. CH /\ ( A i^i B ) e. CH /\ ( ( x vH A ) i^i B ) e. CH ) -> ( ( x C_ ( ( x vH A ) i^i B ) /\ ( A i^i B ) C_ ( ( x vH A ) i^i B ) ) <-> ( x vH ( A i^i B ) ) C_ ( ( x vH A ) i^i B ) ) ) | 
						
							| 20 | 18 19 | mp3an2 |  |-  ( ( x e. CH /\ ( ( x vH A ) i^i B ) e. CH ) -> ( ( x C_ ( ( x vH A ) i^i B ) /\ ( A i^i B ) C_ ( ( x vH A ) i^i B ) ) <-> ( x vH ( A i^i B ) ) C_ ( ( x vH A ) i^i B ) ) ) | 
						
							| 21 | 17 20 | mpdan |  |-  ( x e. CH -> ( ( x C_ ( ( x vH A ) i^i B ) /\ ( A i^i B ) C_ ( ( x vH A ) i^i B ) ) <-> ( x vH ( A i^i B ) ) C_ ( ( x vH A ) i^i B ) ) ) | 
						
							| 22 | 12 21 | sylibd |  |-  ( x e. CH -> ( x C_ B -> ( x vH ( A i^i B ) ) C_ ( ( x vH A ) i^i B ) ) ) | 
						
							| 23 |  | eqss |  |-  ( ( ( x vH A ) i^i B ) = ( x vH ( A i^i B ) ) <-> ( ( ( x vH A ) i^i B ) C_ ( x vH ( A i^i B ) ) /\ ( x vH ( A i^i B ) ) C_ ( ( x vH A ) i^i B ) ) ) | 
						
							| 24 | 23 | rbaib |  |-  ( ( x vH ( A i^i B ) ) C_ ( ( x vH A ) i^i B ) -> ( ( ( x vH A ) i^i B ) = ( x vH ( A i^i B ) ) <-> ( ( x vH A ) i^i B ) C_ ( x vH ( A i^i B ) ) ) ) | 
						
							| 25 | 22 24 | syl6 |  |-  ( x e. CH -> ( x C_ B -> ( ( ( x vH A ) i^i B ) = ( x vH ( A i^i B ) ) <-> ( ( x vH A ) i^i B ) C_ ( x vH ( A i^i B ) ) ) ) ) | 
						
							| 26 | 25 | adantld |  |-  ( x e. CH -> ( ( ( A i^i B ) C_ x /\ x C_ B ) -> ( ( ( x vH A ) i^i B ) = ( x vH ( A i^i B ) ) <-> ( ( x vH A ) i^i B ) C_ ( x vH ( A i^i B ) ) ) ) ) | 
						
							| 27 | 26 | pm5.74d |  |-  ( x e. CH -> ( ( ( ( A i^i B ) C_ x /\ x C_ B ) -> ( ( x vH A ) i^i B ) = ( x vH ( A i^i B ) ) ) <-> ( ( ( A i^i B ) C_ x /\ x C_ B ) -> ( ( x vH A ) i^i B ) C_ ( x vH ( A i^i B ) ) ) ) ) | 
						
							| 28 | 2 1 | chub2i |  |-  B C_ ( A vH B ) | 
						
							| 29 |  | sstr |  |-  ( ( x C_ B /\ B C_ ( A vH B ) ) -> x C_ ( A vH B ) ) | 
						
							| 30 | 28 29 | mpan2 |  |-  ( x C_ B -> x C_ ( A vH B ) ) | 
						
							| 31 | 30 | pm4.71ri |  |-  ( x C_ B <-> ( x C_ ( A vH B ) /\ x C_ B ) ) | 
						
							| 32 | 31 | anbi2i |  |-  ( ( ( A i^i B ) C_ x /\ x C_ B ) <-> ( ( A i^i B ) C_ x /\ ( x C_ ( A vH B ) /\ x C_ B ) ) ) | 
						
							| 33 |  | anass |  |-  ( ( ( ( A i^i B ) C_ x /\ x C_ ( A vH B ) ) /\ x C_ B ) <-> ( ( A i^i B ) C_ x /\ ( x C_ ( A vH B ) /\ x C_ B ) ) ) | 
						
							| 34 | 32 33 | bitr4i |  |-  ( ( ( A i^i B ) C_ x /\ x C_ B ) <-> ( ( ( A i^i B ) C_ x /\ x C_ ( A vH B ) ) /\ x C_ B ) ) | 
						
							| 35 | 34 | imbi1i |  |-  ( ( ( ( A i^i B ) C_ x /\ x C_ B ) -> ( ( x vH A ) i^i B ) = ( x vH ( A i^i B ) ) ) <-> ( ( ( ( A i^i B ) C_ x /\ x C_ ( A vH B ) ) /\ x C_ B ) -> ( ( x vH A ) i^i B ) = ( x vH ( A i^i B ) ) ) ) | 
						
							| 36 | 27 35 | bitr3di |  |-  ( x e. CH -> ( ( ( ( A i^i B ) C_ x /\ x C_ B ) -> ( ( x vH A ) i^i B ) C_ ( x vH ( A i^i B ) ) ) <-> ( ( ( ( A i^i B ) C_ x /\ x C_ ( A vH B ) ) /\ x C_ B ) -> ( ( x vH A ) i^i B ) = ( x vH ( A i^i B ) ) ) ) ) | 
						
							| 37 |  | impexp |  |-  ( ( ( ( ( A i^i B ) C_ x /\ x C_ ( A vH B ) ) /\ x C_ B ) -> ( ( x vH A ) i^i B ) = ( x vH ( A i^i B ) ) ) <-> ( ( ( A i^i B ) C_ x /\ x C_ ( A vH B ) ) -> ( x C_ B -> ( ( x vH A ) i^i B ) = ( x vH ( A i^i B ) ) ) ) ) | 
						
							| 38 | 36 37 | bitrdi |  |-  ( x e. CH -> ( ( ( ( A i^i B ) C_ x /\ x C_ B ) -> ( ( x vH A ) i^i B ) C_ ( x vH ( A i^i B ) ) ) <-> ( ( ( A i^i B ) C_ x /\ x C_ ( A vH B ) ) -> ( x C_ B -> ( ( x vH A ) i^i B ) = ( x vH ( A i^i B ) ) ) ) ) ) | 
						
							| 39 | 38 | ralbiia |  |-  ( A. x e. CH ( ( ( A i^i B ) C_ x /\ x C_ B ) -> ( ( x vH A ) i^i B ) C_ ( x vH ( A i^i B ) ) ) <-> A. x e. CH ( ( ( A i^i B ) C_ x /\ x C_ ( A vH B ) ) -> ( x C_ B -> ( ( x vH A ) i^i B ) = ( x vH ( A i^i B ) ) ) ) ) | 
						
							| 40 | 1 2 | mdsl1i |  |-  ( A. x e. CH ( ( ( A i^i B ) C_ x /\ x C_ ( A vH B ) ) -> ( x C_ B -> ( ( x vH A ) i^i B ) = ( x vH ( A i^i B ) ) ) ) <-> A MH B ) | 
						
							| 41 | 39 40 | bitr2i |  |-  ( A MH B <-> A. x e. CH ( ( ( A i^i B ) C_ x /\ x C_ B ) -> ( ( x vH A ) i^i B ) C_ ( x vH ( A i^i B ) ) ) ) |