| Step | Hyp | Ref | Expression | 
						
							| 1 |  | mdslle1.1 |  |-  A e. CH | 
						
							| 2 |  | mdslle1.2 |  |-  B e. CH | 
						
							| 3 |  | mdslle1.3 |  |-  C e. CH | 
						
							| 4 |  | mdslle1.4 |  |-  D e. CH | 
						
							| 5 |  | ssin |  |-  ( ( A C_ C /\ A C_ D ) <-> A C_ ( C i^i D ) ) | 
						
							| 6 | 5 | bicomi |  |-  ( A C_ ( C i^i D ) <-> ( A C_ C /\ A C_ D ) ) | 
						
							| 7 | 1 2 | chjcli |  |-  ( A vH B ) e. CH | 
						
							| 8 | 3 4 7 | chlubi |  |-  ( ( C C_ ( A vH B ) /\ D C_ ( A vH B ) ) <-> ( C vH D ) C_ ( A vH B ) ) | 
						
							| 9 | 8 | bicomi |  |-  ( ( C vH D ) C_ ( A vH B ) <-> ( C C_ ( A vH B ) /\ D C_ ( A vH B ) ) ) | 
						
							| 10 | 6 9 | anbi12i |  |-  ( ( A C_ ( C i^i D ) /\ ( C vH D ) C_ ( A vH B ) ) <-> ( ( A C_ C /\ A C_ D ) /\ ( C C_ ( A vH B ) /\ D C_ ( A vH B ) ) ) ) | 
						
							| 11 |  | simpr |  |-  ( ( A MH B /\ B MH* A ) -> B MH* A ) | 
						
							| 12 |  | simpl |  |-  ( ( A C_ C /\ A C_ D ) -> A C_ C ) | 
						
							| 13 |  | simpl |  |-  ( ( C C_ ( A vH B ) /\ D C_ ( A vH B ) ) -> C C_ ( A vH B ) ) | 
						
							| 14 | 1 2 3 | 3pm3.2i |  |-  ( A e. CH /\ B e. CH /\ C e. CH ) | 
						
							| 15 |  | dmdsl3 |  |-  ( ( ( A e. CH /\ B e. CH /\ C e. CH ) /\ ( B MH* A /\ A C_ C /\ C C_ ( A vH B ) ) ) -> ( ( C i^i B ) vH A ) = C ) | 
						
							| 16 | 14 15 | mpan |  |-  ( ( B MH* A /\ A C_ C /\ C C_ ( A vH B ) ) -> ( ( C i^i B ) vH A ) = C ) | 
						
							| 17 | 11 12 13 16 | syl3an |  |-  ( ( ( A MH B /\ B MH* A ) /\ ( A C_ C /\ A C_ D ) /\ ( C C_ ( A vH B ) /\ D C_ ( A vH B ) ) ) -> ( ( C i^i B ) vH A ) = C ) | 
						
							| 18 | 3 2 | chincli |  |-  ( C i^i B ) e. CH | 
						
							| 19 | 4 2 | chincli |  |-  ( D i^i B ) e. CH | 
						
							| 20 | 18 19 | chub1i |  |-  ( C i^i B ) C_ ( ( C i^i B ) vH ( D i^i B ) ) | 
						
							| 21 | 18 19 | chjcli |  |-  ( ( C i^i B ) vH ( D i^i B ) ) e. CH | 
						
							| 22 | 18 21 1 | chlej1i |  |-  ( ( C i^i B ) C_ ( ( C i^i B ) vH ( D i^i B ) ) -> ( ( C i^i B ) vH A ) C_ ( ( ( C i^i B ) vH ( D i^i B ) ) vH A ) ) | 
						
							| 23 | 20 22 | mp1i |  |-  ( ( ( A MH B /\ B MH* A ) /\ ( A C_ C /\ A C_ D ) /\ ( C C_ ( A vH B ) /\ D C_ ( A vH B ) ) ) -> ( ( C i^i B ) vH A ) C_ ( ( ( C i^i B ) vH ( D i^i B ) ) vH A ) ) | 
						
							| 24 | 17 23 | eqsstrrd |  |-  ( ( ( A MH B /\ B MH* A ) /\ ( A C_ C /\ A C_ D ) /\ ( C C_ ( A vH B ) /\ D C_ ( A vH B ) ) ) -> C C_ ( ( ( C i^i B ) vH ( D i^i B ) ) vH A ) ) | 
						
							| 25 |  | simpr |  |-  ( ( A C_ C /\ A C_ D ) -> A C_ D ) | 
						
							| 26 |  | simpr |  |-  ( ( C C_ ( A vH B ) /\ D C_ ( A vH B ) ) -> D C_ ( A vH B ) ) | 
						
							| 27 | 1 2 4 | 3pm3.2i |  |-  ( A e. CH /\ B e. CH /\ D e. CH ) | 
						
							| 28 |  | dmdsl3 |  |-  ( ( ( A e. CH /\ B e. CH /\ D e. CH ) /\ ( B MH* A /\ A C_ D /\ D C_ ( A vH B ) ) ) -> ( ( D i^i B ) vH A ) = D ) | 
						
							| 29 | 27 28 | mpan |  |-  ( ( B MH* A /\ A C_ D /\ D C_ ( A vH B ) ) -> ( ( D i^i B ) vH A ) = D ) | 
						
							| 30 | 11 25 26 29 | syl3an |  |-  ( ( ( A MH B /\ B MH* A ) /\ ( A C_ C /\ A C_ D ) /\ ( C C_ ( A vH B ) /\ D C_ ( A vH B ) ) ) -> ( ( D i^i B ) vH A ) = D ) | 
						
							| 31 | 19 18 | chub2i |  |-  ( D i^i B ) C_ ( ( C i^i B ) vH ( D i^i B ) ) | 
						
							| 32 | 19 21 1 | chlej1i |  |-  ( ( D i^i B ) C_ ( ( C i^i B ) vH ( D i^i B ) ) -> ( ( D i^i B ) vH A ) C_ ( ( ( C i^i B ) vH ( D i^i B ) ) vH A ) ) | 
						
							| 33 | 31 32 | mp1i |  |-  ( ( ( A MH B /\ B MH* A ) /\ ( A C_ C /\ A C_ D ) /\ ( C C_ ( A vH B ) /\ D C_ ( A vH B ) ) ) -> ( ( D i^i B ) vH A ) C_ ( ( ( C i^i B ) vH ( D i^i B ) ) vH A ) ) | 
						
							| 34 | 30 33 | eqsstrrd |  |-  ( ( ( A MH B /\ B MH* A ) /\ ( A C_ C /\ A C_ D ) /\ ( C C_ ( A vH B ) /\ D C_ ( A vH B ) ) ) -> D C_ ( ( ( C i^i B ) vH ( D i^i B ) ) vH A ) ) | 
						
							| 35 | 24 34 | jca |  |-  ( ( ( A MH B /\ B MH* A ) /\ ( A C_ C /\ A C_ D ) /\ ( C C_ ( A vH B ) /\ D C_ ( A vH B ) ) ) -> ( C C_ ( ( ( C i^i B ) vH ( D i^i B ) ) vH A ) /\ D C_ ( ( ( C i^i B ) vH ( D i^i B ) ) vH A ) ) ) | 
						
							| 36 | 21 1 | chjcli |  |-  ( ( ( C i^i B ) vH ( D i^i B ) ) vH A ) e. CH | 
						
							| 37 | 3 4 36 | chlubi |  |-  ( ( C C_ ( ( ( C i^i B ) vH ( D i^i B ) ) vH A ) /\ D C_ ( ( ( C i^i B ) vH ( D i^i B ) ) vH A ) ) <-> ( C vH D ) C_ ( ( ( C i^i B ) vH ( D i^i B ) ) vH A ) ) | 
						
							| 38 | 35 37 | sylib |  |-  ( ( ( A MH B /\ B MH* A ) /\ ( A C_ C /\ A C_ D ) /\ ( C C_ ( A vH B ) /\ D C_ ( A vH B ) ) ) -> ( C vH D ) C_ ( ( ( C i^i B ) vH ( D i^i B ) ) vH A ) ) | 
						
							| 39 | 38 | ssrind |  |-  ( ( ( A MH B /\ B MH* A ) /\ ( A C_ C /\ A C_ D ) /\ ( C C_ ( A vH B ) /\ D C_ ( A vH B ) ) ) -> ( ( C vH D ) i^i B ) C_ ( ( ( ( C i^i B ) vH ( D i^i B ) ) vH A ) i^i B ) ) | 
						
							| 40 |  | simpl |  |-  ( ( A MH B /\ B MH* A ) -> A MH B ) | 
						
							| 41 |  | ssrin |  |-  ( A C_ C -> ( A i^i B ) C_ ( C i^i B ) ) | 
						
							| 42 | 41 20 | sstrdi |  |-  ( A C_ C -> ( A i^i B ) C_ ( ( C i^i B ) vH ( D i^i B ) ) ) | 
						
							| 43 | 42 | adantr |  |-  ( ( A C_ C /\ A C_ D ) -> ( A i^i B ) C_ ( ( C i^i B ) vH ( D i^i B ) ) ) | 
						
							| 44 |  | inss2 |  |-  ( C i^i B ) C_ B | 
						
							| 45 |  | inss2 |  |-  ( D i^i B ) C_ B | 
						
							| 46 | 18 19 2 | chlubi |  |-  ( ( ( C i^i B ) C_ B /\ ( D i^i B ) C_ B ) <-> ( ( C i^i B ) vH ( D i^i B ) ) C_ B ) | 
						
							| 47 | 46 | bicomi |  |-  ( ( ( C i^i B ) vH ( D i^i B ) ) C_ B <-> ( ( C i^i B ) C_ B /\ ( D i^i B ) C_ B ) ) | 
						
							| 48 | 44 45 47 | mpbir2an |  |-  ( ( C i^i B ) vH ( D i^i B ) ) C_ B | 
						
							| 49 | 48 | a1i |  |-  ( ( C C_ ( A vH B ) /\ D C_ ( A vH B ) ) -> ( ( C i^i B ) vH ( D i^i B ) ) C_ B ) | 
						
							| 50 | 1 2 21 | 3pm3.2i |  |-  ( A e. CH /\ B e. CH /\ ( ( C i^i B ) vH ( D i^i B ) ) e. CH ) | 
						
							| 51 |  | mdsl3 |  |-  ( ( ( A e. CH /\ B e. CH /\ ( ( C i^i B ) vH ( D i^i B ) ) e. CH ) /\ ( A MH B /\ ( A i^i B ) C_ ( ( C i^i B ) vH ( D i^i B ) ) /\ ( ( C i^i B ) vH ( D i^i B ) ) C_ B ) ) -> ( ( ( ( C i^i B ) vH ( D i^i B ) ) vH A ) i^i B ) = ( ( C i^i B ) vH ( D i^i B ) ) ) | 
						
							| 52 | 50 51 | mpan |  |-  ( ( A MH B /\ ( A i^i B ) C_ ( ( C i^i B ) vH ( D i^i B ) ) /\ ( ( C i^i B ) vH ( D i^i B ) ) C_ B ) -> ( ( ( ( C i^i B ) vH ( D i^i B ) ) vH A ) i^i B ) = ( ( C i^i B ) vH ( D i^i B ) ) ) | 
						
							| 53 | 40 43 49 52 | syl3an |  |-  ( ( ( A MH B /\ B MH* A ) /\ ( A C_ C /\ A C_ D ) /\ ( C C_ ( A vH B ) /\ D C_ ( A vH B ) ) ) -> ( ( ( ( C i^i B ) vH ( D i^i B ) ) vH A ) i^i B ) = ( ( C i^i B ) vH ( D i^i B ) ) ) | 
						
							| 54 | 39 53 | sseqtrd |  |-  ( ( ( A MH B /\ B MH* A ) /\ ( A C_ C /\ A C_ D ) /\ ( C C_ ( A vH B ) /\ D C_ ( A vH B ) ) ) -> ( ( C vH D ) i^i B ) C_ ( ( C i^i B ) vH ( D i^i B ) ) ) | 
						
							| 55 | 54 | 3expb |  |-  ( ( ( A MH B /\ B MH* A ) /\ ( ( A C_ C /\ A C_ D ) /\ ( C C_ ( A vH B ) /\ D C_ ( A vH B ) ) ) ) -> ( ( C vH D ) i^i B ) C_ ( ( C i^i B ) vH ( D i^i B ) ) ) | 
						
							| 56 | 10 55 | sylan2b |  |-  ( ( ( A MH B /\ B MH* A ) /\ ( A C_ ( C i^i D ) /\ ( C vH D ) C_ ( A vH B ) ) ) -> ( ( C vH D ) i^i B ) C_ ( ( C i^i B ) vH ( D i^i B ) ) ) | 
						
							| 57 | 3 4 2 | lediri |  |-  ( ( C i^i B ) vH ( D i^i B ) ) C_ ( ( C vH D ) i^i B ) | 
						
							| 58 | 57 | a1i |  |-  ( ( ( A MH B /\ B MH* A ) /\ ( A C_ ( C i^i D ) /\ ( C vH D ) C_ ( A vH B ) ) ) -> ( ( C i^i B ) vH ( D i^i B ) ) C_ ( ( C vH D ) i^i B ) ) | 
						
							| 59 | 56 58 | eqssd |  |-  ( ( ( A MH B /\ B MH* A ) /\ ( A C_ ( C i^i D ) /\ ( C vH D ) C_ ( A vH B ) ) ) -> ( ( C vH D ) i^i B ) = ( ( C i^i B ) vH ( D i^i B ) ) ) |