| Step | Hyp | Ref | Expression | 
						
							| 1 |  | mdexch.1 |  |-  A e. CH | 
						
							| 2 |  | mdexch.2 |  |-  B e. CH | 
						
							| 3 |  | mdexch.3 |  |-  C e. CH | 
						
							| 4 |  | chjass |  |-  ( ( C e. CH /\ A e. CH /\ x e. CH ) -> ( ( C vH A ) vH x ) = ( C vH ( A vH x ) ) ) | 
						
							| 5 | 3 1 4 | mp3an12 |  |-  ( x e. CH -> ( ( C vH A ) vH x ) = ( C vH ( A vH x ) ) ) | 
						
							| 6 | 3 1 | chjcli |  |-  ( C vH A ) e. CH | 
						
							| 7 |  | chjcom |  |-  ( ( x e. CH /\ ( C vH A ) e. CH ) -> ( x vH ( C vH A ) ) = ( ( C vH A ) vH x ) ) | 
						
							| 8 | 6 7 | mpan2 |  |-  ( x e. CH -> ( x vH ( C vH A ) ) = ( ( C vH A ) vH x ) ) | 
						
							| 9 |  | chjcl |  |-  ( ( A e. CH /\ x e. CH ) -> ( A vH x ) e. CH ) | 
						
							| 10 | 1 9 | mpan |  |-  ( x e. CH -> ( A vH x ) e. CH ) | 
						
							| 11 |  | chjcom |  |-  ( ( ( A vH x ) e. CH /\ C e. CH ) -> ( ( A vH x ) vH C ) = ( C vH ( A vH x ) ) ) | 
						
							| 12 | 10 3 11 | sylancl |  |-  ( x e. CH -> ( ( A vH x ) vH C ) = ( C vH ( A vH x ) ) ) | 
						
							| 13 | 5 8 12 | 3eqtr4d |  |-  ( x e. CH -> ( x vH ( C vH A ) ) = ( ( A vH x ) vH C ) ) | 
						
							| 14 | 13 | ineq1d |  |-  ( x e. CH -> ( ( x vH ( C vH A ) ) i^i B ) = ( ( ( A vH x ) vH C ) i^i B ) ) | 
						
							| 15 |  | inass |  |-  ( ( ( ( A vH x ) vH C ) i^i ( A vH B ) ) i^i B ) = ( ( ( A vH x ) vH C ) i^i ( ( A vH B ) i^i B ) ) | 
						
							| 16 |  | incom |  |-  ( ( A vH B ) i^i B ) = ( B i^i ( A vH B ) ) | 
						
							| 17 | 1 2 | chjcomi |  |-  ( A vH B ) = ( B vH A ) | 
						
							| 18 | 17 | ineq2i |  |-  ( B i^i ( A vH B ) ) = ( B i^i ( B vH A ) ) | 
						
							| 19 | 2 1 | chabs2i |  |-  ( B i^i ( B vH A ) ) = B | 
						
							| 20 | 18 19 | eqtri |  |-  ( B i^i ( A vH B ) ) = B | 
						
							| 21 | 16 20 | eqtri |  |-  ( ( A vH B ) i^i B ) = B | 
						
							| 22 | 21 | ineq2i |  |-  ( ( ( A vH x ) vH C ) i^i ( ( A vH B ) i^i B ) ) = ( ( ( A vH x ) vH C ) i^i B ) | 
						
							| 23 | 15 22 | eqtri |  |-  ( ( ( ( A vH x ) vH C ) i^i ( A vH B ) ) i^i B ) = ( ( ( A vH x ) vH C ) i^i B ) | 
						
							| 24 | 14 23 | eqtr4di |  |-  ( x e. CH -> ( ( x vH ( C vH A ) ) i^i B ) = ( ( ( ( A vH x ) vH C ) i^i ( A vH B ) ) i^i B ) ) | 
						
							| 25 | 24 | ad2antrr |  |-  ( ( ( x e. CH /\ x C_ B ) /\ ( C MH ( A vH B ) /\ ( C i^i ( A vH B ) ) C_ A ) ) -> ( ( x vH ( C vH A ) ) i^i B ) = ( ( ( ( A vH x ) vH C ) i^i ( A vH B ) ) i^i B ) ) | 
						
							| 26 |  | chlej2 |  |-  ( ( ( x e. CH /\ B e. CH /\ A e. CH ) /\ x C_ B ) -> ( A vH x ) C_ ( A vH B ) ) | 
						
							| 27 | 26 | ex |  |-  ( ( x e. CH /\ B e. CH /\ A e. CH ) -> ( x C_ B -> ( A vH x ) C_ ( A vH B ) ) ) | 
						
							| 28 | 2 1 27 | mp3an23 |  |-  ( x e. CH -> ( x C_ B -> ( A vH x ) C_ ( A vH B ) ) ) | 
						
							| 29 | 1 2 | chjcli |  |-  ( A vH B ) e. CH | 
						
							| 30 |  | mdi |  |-  ( ( ( C e. CH /\ ( A vH B ) e. CH /\ ( A vH x ) e. CH ) /\ ( C MH ( A vH B ) /\ ( A vH x ) C_ ( A vH B ) ) ) -> ( ( ( A vH x ) vH C ) i^i ( A vH B ) ) = ( ( A vH x ) vH ( C i^i ( A vH B ) ) ) ) | 
						
							| 31 | 30 | exp32 |  |-  ( ( C e. CH /\ ( A vH B ) e. CH /\ ( A vH x ) e. CH ) -> ( C MH ( A vH B ) -> ( ( A vH x ) C_ ( A vH B ) -> ( ( ( A vH x ) vH C ) i^i ( A vH B ) ) = ( ( A vH x ) vH ( C i^i ( A vH B ) ) ) ) ) ) | 
						
							| 32 | 3 29 31 | mp3an12 |  |-  ( ( A vH x ) e. CH -> ( C MH ( A vH B ) -> ( ( A vH x ) C_ ( A vH B ) -> ( ( ( A vH x ) vH C ) i^i ( A vH B ) ) = ( ( A vH x ) vH ( C i^i ( A vH B ) ) ) ) ) ) | 
						
							| 33 | 10 32 | syl |  |-  ( x e. CH -> ( C MH ( A vH B ) -> ( ( A vH x ) C_ ( A vH B ) -> ( ( ( A vH x ) vH C ) i^i ( A vH B ) ) = ( ( A vH x ) vH ( C i^i ( A vH B ) ) ) ) ) ) | 
						
							| 34 | 33 | com23 |  |-  ( x e. CH -> ( ( A vH x ) C_ ( A vH B ) -> ( C MH ( A vH B ) -> ( ( ( A vH x ) vH C ) i^i ( A vH B ) ) = ( ( A vH x ) vH ( C i^i ( A vH B ) ) ) ) ) ) | 
						
							| 35 | 28 34 | syld |  |-  ( x e. CH -> ( x C_ B -> ( C MH ( A vH B ) -> ( ( ( A vH x ) vH C ) i^i ( A vH B ) ) = ( ( A vH x ) vH ( C i^i ( A vH B ) ) ) ) ) ) | 
						
							| 36 | 35 | imp31 |  |-  ( ( ( x e. CH /\ x C_ B ) /\ C MH ( A vH B ) ) -> ( ( ( A vH x ) vH C ) i^i ( A vH B ) ) = ( ( A vH x ) vH ( C i^i ( A vH B ) ) ) ) | 
						
							| 37 | 36 | adantrr |  |-  ( ( ( x e. CH /\ x C_ B ) /\ ( C MH ( A vH B ) /\ ( C i^i ( A vH B ) ) C_ A ) ) -> ( ( ( A vH x ) vH C ) i^i ( A vH B ) ) = ( ( A vH x ) vH ( C i^i ( A vH B ) ) ) ) | 
						
							| 38 | 3 29 | chincli |  |-  ( C i^i ( A vH B ) ) e. CH | 
						
							| 39 |  | chlej2 |  |-  ( ( ( ( C i^i ( A vH B ) ) e. CH /\ A e. CH /\ ( A vH x ) e. CH ) /\ ( C i^i ( A vH B ) ) C_ A ) -> ( ( A vH x ) vH ( C i^i ( A vH B ) ) ) C_ ( ( A vH x ) vH A ) ) | 
						
							| 40 | 39 | ex |  |-  ( ( ( C i^i ( A vH B ) ) e. CH /\ A e. CH /\ ( A vH x ) e. CH ) -> ( ( C i^i ( A vH B ) ) C_ A -> ( ( A vH x ) vH ( C i^i ( A vH B ) ) ) C_ ( ( A vH x ) vH A ) ) ) | 
						
							| 41 | 38 1 40 | mp3an12 |  |-  ( ( A vH x ) e. CH -> ( ( C i^i ( A vH B ) ) C_ A -> ( ( A vH x ) vH ( C i^i ( A vH B ) ) ) C_ ( ( A vH x ) vH A ) ) ) | 
						
							| 42 | 10 41 | syl |  |-  ( x e. CH -> ( ( C i^i ( A vH B ) ) C_ A -> ( ( A vH x ) vH ( C i^i ( A vH B ) ) ) C_ ( ( A vH x ) vH A ) ) ) | 
						
							| 43 | 42 | imp |  |-  ( ( x e. CH /\ ( C i^i ( A vH B ) ) C_ A ) -> ( ( A vH x ) vH ( C i^i ( A vH B ) ) ) C_ ( ( A vH x ) vH A ) ) | 
						
							| 44 |  | chjcom |  |-  ( ( ( A vH x ) e. CH /\ A e. CH ) -> ( ( A vH x ) vH A ) = ( A vH ( A vH x ) ) ) | 
						
							| 45 | 10 1 44 | sylancl |  |-  ( x e. CH -> ( ( A vH x ) vH A ) = ( A vH ( A vH x ) ) ) | 
						
							| 46 | 1 | chjidmi |  |-  ( A vH A ) = A | 
						
							| 47 | 46 | oveq1i |  |-  ( ( A vH A ) vH x ) = ( A vH x ) | 
						
							| 48 |  | chjass |  |-  ( ( A e. CH /\ A e. CH /\ x e. CH ) -> ( ( A vH A ) vH x ) = ( A vH ( A vH x ) ) ) | 
						
							| 49 | 1 1 48 | mp3an12 |  |-  ( x e. CH -> ( ( A vH A ) vH x ) = ( A vH ( A vH x ) ) ) | 
						
							| 50 |  | chjcom |  |-  ( ( A e. CH /\ x e. CH ) -> ( A vH x ) = ( x vH A ) ) | 
						
							| 51 | 1 50 | mpan |  |-  ( x e. CH -> ( A vH x ) = ( x vH A ) ) | 
						
							| 52 | 47 49 51 | 3eqtr3a |  |-  ( x e. CH -> ( A vH ( A vH x ) ) = ( x vH A ) ) | 
						
							| 53 | 45 52 | eqtrd |  |-  ( x e. CH -> ( ( A vH x ) vH A ) = ( x vH A ) ) | 
						
							| 54 | 53 | adantr |  |-  ( ( x e. CH /\ ( C i^i ( A vH B ) ) C_ A ) -> ( ( A vH x ) vH A ) = ( x vH A ) ) | 
						
							| 55 | 43 54 | sseqtrd |  |-  ( ( x e. CH /\ ( C i^i ( A vH B ) ) C_ A ) -> ( ( A vH x ) vH ( C i^i ( A vH B ) ) ) C_ ( x vH A ) ) | 
						
							| 56 | 55 | ad2ant2rl |  |-  ( ( ( x e. CH /\ x C_ B ) /\ ( C MH ( A vH B ) /\ ( C i^i ( A vH B ) ) C_ A ) ) -> ( ( A vH x ) vH ( C i^i ( A vH B ) ) ) C_ ( x vH A ) ) | 
						
							| 57 | 37 56 | eqsstrd |  |-  ( ( ( x e. CH /\ x C_ B ) /\ ( C MH ( A vH B ) /\ ( C i^i ( A vH B ) ) C_ A ) ) -> ( ( ( A vH x ) vH C ) i^i ( A vH B ) ) C_ ( x vH A ) ) | 
						
							| 58 | 57 | ssrind |  |-  ( ( ( x e. CH /\ x C_ B ) /\ ( C MH ( A vH B ) /\ ( C i^i ( A vH B ) ) C_ A ) ) -> ( ( ( ( A vH x ) vH C ) i^i ( A vH B ) ) i^i B ) C_ ( ( x vH A ) i^i B ) ) | 
						
							| 59 | 25 58 | eqsstrd |  |-  ( ( ( x e. CH /\ x C_ B ) /\ ( C MH ( A vH B ) /\ ( C i^i ( A vH B ) ) C_ A ) ) -> ( ( x vH ( C vH A ) ) i^i B ) C_ ( ( x vH A ) i^i B ) ) | 
						
							| 60 | 59 | adantrl |  |-  ( ( ( x e. CH /\ x C_ B ) /\ ( A MH B /\ ( C MH ( A vH B ) /\ ( C i^i ( A vH B ) ) C_ A ) ) ) -> ( ( x vH ( C vH A ) ) i^i B ) C_ ( ( x vH A ) i^i B ) ) | 
						
							| 61 |  | 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 ) ) ) | 
						
							| 62 | 61 | exp32 |  |-  ( ( 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 ) ) ) ) ) | 
						
							| 63 | 1 2 62 | mp3an12 |  |-  ( x e. CH -> ( A MH B -> ( x C_ B -> ( ( x vH A ) i^i B ) = ( x vH ( A i^i B ) ) ) ) ) | 
						
							| 64 | 63 | com23 |  |-  ( x e. CH -> ( x C_ B -> ( A MH B -> ( ( x vH A ) i^i B ) = ( x vH ( A i^i B ) ) ) ) ) | 
						
							| 65 | 64 | imp31 |  |-  ( ( ( x e. CH /\ x C_ B ) /\ A MH B ) -> ( ( x vH A ) i^i B ) = ( x vH ( A i^i B ) ) ) | 
						
							| 66 | 1 3 | chub2i |  |-  A C_ ( C vH A ) | 
						
							| 67 |  | ssrin |  |-  ( A C_ ( C vH A ) -> ( A i^i B ) C_ ( ( C vH A ) i^i B ) ) | 
						
							| 68 | 66 67 | ax-mp |  |-  ( A i^i B ) C_ ( ( C vH A ) i^i B ) | 
						
							| 69 | 1 2 | chincli |  |-  ( A i^i B ) e. CH | 
						
							| 70 | 6 2 | chincli |  |-  ( ( C vH A ) i^i B ) e. CH | 
						
							| 71 |  | chlej2 |  |-  ( ( ( ( A i^i B ) e. CH /\ ( ( C vH A ) i^i B ) e. CH /\ x e. CH ) /\ ( A i^i B ) C_ ( ( C vH A ) i^i B ) ) -> ( x vH ( A i^i B ) ) C_ ( x vH ( ( C vH A ) i^i B ) ) ) | 
						
							| 72 | 71 | ex |  |-  ( ( ( A i^i B ) e. CH /\ ( ( C vH A ) i^i B ) e. CH /\ x e. CH ) -> ( ( A i^i B ) C_ ( ( C vH A ) i^i B ) -> ( x vH ( A i^i B ) ) C_ ( x vH ( ( C vH A ) i^i B ) ) ) ) | 
						
							| 73 | 69 70 72 | mp3an12 |  |-  ( x e. CH -> ( ( A i^i B ) C_ ( ( C vH A ) i^i B ) -> ( x vH ( A i^i B ) ) C_ ( x vH ( ( C vH A ) i^i B ) ) ) ) | 
						
							| 74 | 68 73 | mpi |  |-  ( x e. CH -> ( x vH ( A i^i B ) ) C_ ( x vH ( ( C vH A ) i^i B ) ) ) | 
						
							| 75 | 74 | ad2antrr |  |-  ( ( ( x e. CH /\ x C_ B ) /\ A MH B ) -> ( x vH ( A i^i B ) ) C_ ( x vH ( ( C vH A ) i^i B ) ) ) | 
						
							| 76 | 65 75 | eqsstrd |  |-  ( ( ( x e. CH /\ x C_ B ) /\ A MH B ) -> ( ( x vH A ) i^i B ) C_ ( x vH ( ( C vH A ) i^i B ) ) ) | 
						
							| 77 | 76 | adantrr |  |-  ( ( ( x e. CH /\ x C_ B ) /\ ( A MH B /\ ( C MH ( A vH B ) /\ ( C i^i ( A vH B ) ) C_ A ) ) ) -> ( ( x vH A ) i^i B ) C_ ( x vH ( ( C vH A ) i^i B ) ) ) | 
						
							| 78 | 60 77 | sstrd |  |-  ( ( ( x e. CH /\ x C_ B ) /\ ( A MH B /\ ( C MH ( A vH B ) /\ ( C i^i ( A vH B ) ) C_ A ) ) ) -> ( ( x vH ( C vH A ) ) i^i B ) C_ ( x vH ( ( C vH A ) i^i B ) ) ) | 
						
							| 79 | 78 | exp31 |  |-  ( x e. CH -> ( x C_ B -> ( ( A MH B /\ ( C MH ( A vH B ) /\ ( C i^i ( A vH B ) ) C_ A ) ) -> ( ( x vH ( C vH A ) ) i^i B ) C_ ( x vH ( ( C vH A ) i^i B ) ) ) ) ) | 
						
							| 80 | 79 | com3r |  |-  ( ( A MH B /\ ( C MH ( A vH B ) /\ ( C i^i ( A vH B ) ) C_ A ) ) -> ( x e. CH -> ( x C_ B -> ( ( x vH ( C vH A ) ) i^i B ) C_ ( x vH ( ( C vH A ) i^i B ) ) ) ) ) | 
						
							| 81 | 80 | 3impb |  |-  ( ( A MH B /\ C MH ( A vH B ) /\ ( C i^i ( A vH B ) ) C_ A ) -> ( x e. CH -> ( x C_ B -> ( ( x vH ( C vH A ) ) i^i B ) C_ ( x vH ( ( C vH A ) i^i B ) ) ) ) ) | 
						
							| 82 | 81 | ralrimiv |  |-  ( ( A MH B /\ C MH ( A vH B ) /\ ( C i^i ( A vH B ) ) C_ A ) -> A. x e. CH ( x C_ B -> ( ( x vH ( C vH A ) ) i^i B ) C_ ( x vH ( ( C vH A ) i^i B ) ) ) ) | 
						
							| 83 |  | mdbr2 |  |-  ( ( ( C vH A ) e. CH /\ B e. CH ) -> ( ( C vH A ) MH B <-> A. x e. CH ( x C_ B -> ( ( x vH ( C vH A ) ) i^i B ) C_ ( x vH ( ( C vH A ) i^i B ) ) ) ) ) | 
						
							| 84 | 6 2 83 | mp2an |  |-  ( ( C vH A ) MH B <-> A. x e. CH ( x C_ B -> ( ( x vH ( C vH A ) ) i^i B ) C_ ( x vH ( ( C vH A ) i^i B ) ) ) ) | 
						
							| 85 | 82 84 | sylibr |  |-  ( ( A MH B /\ C MH ( A vH B ) /\ ( C i^i ( A vH B ) ) C_ A ) -> ( C vH A ) MH B ) | 
						
							| 86 | 3 1 | chjcomi |  |-  ( C vH A ) = ( A vH C ) | 
						
							| 87 |  | incom |  |-  ( B i^i ( A vH B ) ) = ( ( A vH B ) i^i B ) | 
						
							| 88 | 18 87 19 | 3eqtr3ri |  |-  B = ( ( A vH B ) i^i B ) | 
						
							| 89 | 86 88 | ineq12i |  |-  ( ( C vH A ) i^i B ) = ( ( A vH C ) i^i ( ( A vH B ) i^i B ) ) | 
						
							| 90 |  | inass |  |-  ( ( ( A vH C ) i^i ( A vH B ) ) i^i B ) = ( ( A vH C ) i^i ( ( A vH B ) i^i B ) ) | 
						
							| 91 | 1 2 | chub1i |  |-  A C_ ( A vH B ) | 
						
							| 92 |  | mdi |  |-  ( ( ( C e. CH /\ ( A vH B ) e. CH /\ A e. CH ) /\ ( C MH ( A vH B ) /\ A C_ ( A vH B ) ) ) -> ( ( A vH C ) i^i ( A vH B ) ) = ( A vH ( C i^i ( A vH B ) ) ) ) | 
						
							| 93 | 92 | exp32 |  |-  ( ( C e. CH /\ ( A vH B ) e. CH /\ A e. CH ) -> ( C MH ( A vH B ) -> ( A C_ ( A vH B ) -> ( ( A vH C ) i^i ( A vH B ) ) = ( A vH ( C i^i ( A vH B ) ) ) ) ) ) | 
						
							| 94 | 3 29 1 93 | mp3an |  |-  ( C MH ( A vH B ) -> ( A C_ ( A vH B ) -> ( ( A vH C ) i^i ( A vH B ) ) = ( A vH ( C i^i ( A vH B ) ) ) ) ) | 
						
							| 95 | 91 94 | mpi |  |-  ( C MH ( A vH B ) -> ( ( A vH C ) i^i ( A vH B ) ) = ( A vH ( C i^i ( A vH B ) ) ) ) | 
						
							| 96 | 1 38 | chjcomi |  |-  ( A vH ( C i^i ( A vH B ) ) ) = ( ( C i^i ( A vH B ) ) vH A ) | 
						
							| 97 | 38 1 | chlejb1i |  |-  ( ( C i^i ( A vH B ) ) C_ A <-> ( ( C i^i ( A vH B ) ) vH A ) = A ) | 
						
							| 98 | 97 | biimpi |  |-  ( ( C i^i ( A vH B ) ) C_ A -> ( ( C i^i ( A vH B ) ) vH A ) = A ) | 
						
							| 99 | 96 98 | eqtrid |  |-  ( ( C i^i ( A vH B ) ) C_ A -> ( A vH ( C i^i ( A vH B ) ) ) = A ) | 
						
							| 100 | 95 99 | sylan9eq |  |-  ( ( C MH ( A vH B ) /\ ( C i^i ( A vH B ) ) C_ A ) -> ( ( A vH C ) i^i ( A vH B ) ) = A ) | 
						
							| 101 | 100 | ineq1d |  |-  ( ( C MH ( A vH B ) /\ ( C i^i ( A vH B ) ) C_ A ) -> ( ( ( A vH C ) i^i ( A vH B ) ) i^i B ) = ( A i^i B ) ) | 
						
							| 102 | 90 101 | eqtr3id |  |-  ( ( C MH ( A vH B ) /\ ( C i^i ( A vH B ) ) C_ A ) -> ( ( A vH C ) i^i ( ( A vH B ) i^i B ) ) = ( A i^i B ) ) | 
						
							| 103 | 89 102 | eqtrid |  |-  ( ( C MH ( A vH B ) /\ ( C i^i ( A vH B ) ) C_ A ) -> ( ( C vH A ) i^i B ) = ( A i^i B ) ) | 
						
							| 104 | 103 | 3adant1 |  |-  ( ( A MH B /\ C MH ( A vH B ) /\ ( C i^i ( A vH B ) ) C_ A ) -> ( ( C vH A ) i^i B ) = ( A i^i B ) ) | 
						
							| 105 | 85 104 | jca |  |-  ( ( A MH B /\ C MH ( A vH B ) /\ ( C i^i ( A vH B ) ) C_ A ) -> ( ( C vH A ) MH B /\ ( ( C vH A ) i^i B ) = ( A i^i B ) ) ) |