| Step | Hyp | Ref | Expression | 
						
							| 1 |  | csmdsym.1 |  |-  A e. CH | 
						
							| 2 |  | csmdsym.2 |  |-  B e. CH | 
						
							| 3 |  | incom |  |-  ( A i^i B ) = ( B i^i A ) | 
						
							| 4 | 3 | sseq1i |  |-  ( ( A i^i B ) C_ x <-> ( B i^i A ) C_ x ) | 
						
							| 5 | 4 | biimpri |  |-  ( ( B i^i A ) C_ x -> ( A i^i B ) C_ x ) | 
						
							| 6 |  | chjcom |  |-  ( ( x e. CH /\ B e. CH ) -> ( x vH B ) = ( B vH x ) ) | 
						
							| 7 | 2 6 | mpan2 |  |-  ( x e. CH -> ( x vH B ) = ( B vH x ) ) | 
						
							| 8 | 7 | ineq1d |  |-  ( x e. CH -> ( ( x vH B ) i^i A ) = ( ( B vH x ) i^i A ) ) | 
						
							| 9 |  | incom |  |-  ( ( B vH x ) i^i A ) = ( A i^i ( B vH x ) ) | 
						
							| 10 | 8 9 | eqtrdi |  |-  ( x e. CH -> ( ( x vH B ) i^i A ) = ( A i^i ( B vH x ) ) ) | 
						
							| 11 | 10 | ad2antlr |  |-  ( ( ( ( A. c e. CH ( c MH B -> B MH* c ) /\ A MH B ) /\ x e. CH ) /\ ( ( A i^i B ) C_ x /\ x C_ A ) ) -> ( ( x vH B ) i^i A ) = ( A i^i ( B vH x ) ) ) | 
						
							| 12 | 2 | a1i |  |-  ( x e. CH -> B e. CH ) | 
						
							| 13 |  | id |  |-  ( x e. CH -> x e. CH ) | 
						
							| 14 | 1 | a1i |  |-  ( x e. CH -> A e. CH ) | 
						
							| 15 | 12 13 14 | 3jca |  |-  ( x e. CH -> ( B e. CH /\ x e. CH /\ A e. CH ) ) | 
						
							| 16 | 15 | ad2antlr |  |-  ( ( ( ( A. c e. CH ( c MH B -> B MH* c ) /\ A MH B ) /\ x e. CH ) /\ ( ( A i^i B ) C_ x /\ x C_ A ) ) -> ( B e. CH /\ x e. CH /\ A e. CH ) ) | 
						
							| 17 |  | inss2 |  |-  ( A i^i B ) C_ B | 
						
							| 18 |  | ssid |  |-  B C_ B | 
						
							| 19 | 17 18 | pm3.2i |  |-  ( ( A i^i B ) C_ B /\ B C_ B ) | 
						
							| 20 |  | sseq2 |  |-  ( x = if ( x e. CH , x , 0H ) -> ( ( A i^i B ) C_ x <-> ( A i^i B ) C_ if ( x e. CH , x , 0H ) ) ) | 
						
							| 21 |  | sseq1 |  |-  ( x = if ( x e. CH , x , 0H ) -> ( x C_ A <-> if ( x e. CH , x , 0H ) C_ A ) ) | 
						
							| 22 | 20 21 | anbi12d |  |-  ( x = if ( x e. CH , x , 0H ) -> ( ( ( A i^i B ) C_ x /\ x C_ A ) <-> ( ( A i^i B ) C_ if ( x e. CH , x , 0H ) /\ if ( x e. CH , x , 0H ) C_ A ) ) ) | 
						
							| 23 | 22 | 3anbi2d |  |-  ( x = if ( x e. CH , x , 0H ) -> ( ( A MH B /\ ( ( A i^i B ) C_ x /\ x C_ A ) /\ ( ( A i^i B ) C_ B /\ B C_ B ) ) <-> ( A MH B /\ ( ( A i^i B ) C_ if ( x e. CH , x , 0H ) /\ if ( x e. CH , x , 0H ) C_ A ) /\ ( ( A i^i B ) C_ B /\ B C_ B ) ) ) ) | 
						
							| 24 |  | breq1 |  |-  ( x = if ( x e. CH , x , 0H ) -> ( x MH B <-> if ( x e. CH , x , 0H ) MH B ) ) | 
						
							| 25 | 23 24 | imbi12d |  |-  ( x = if ( x e. CH , x , 0H ) -> ( ( ( A MH B /\ ( ( A i^i B ) C_ x /\ x C_ A ) /\ ( ( A i^i B ) C_ B /\ B C_ B ) ) -> x MH B ) <-> ( ( A MH B /\ ( ( A i^i B ) C_ if ( x e. CH , x , 0H ) /\ if ( x e. CH , x , 0H ) C_ A ) /\ ( ( A i^i B ) C_ B /\ B C_ B ) ) -> if ( x e. CH , x , 0H ) MH B ) ) ) | 
						
							| 26 |  | h0elch |  |-  0H e. CH | 
						
							| 27 | 26 | elimel |  |-  if ( x e. CH , x , 0H ) e. CH | 
						
							| 28 | 1 2 27 2 | mdslmd4i |  |-  ( ( A MH B /\ ( ( A i^i B ) C_ if ( x e. CH , x , 0H ) /\ if ( x e. CH , x , 0H ) C_ A ) /\ ( ( A i^i B ) C_ B /\ B C_ B ) ) -> if ( x e. CH , x , 0H ) MH B ) | 
						
							| 29 | 25 28 | dedth |  |-  ( x e. CH -> ( ( A MH B /\ ( ( A i^i B ) C_ x /\ x C_ A ) /\ ( ( A i^i B ) C_ B /\ B C_ B ) ) -> x MH B ) ) | 
						
							| 30 | 29 | com12 |  |-  ( ( A MH B /\ ( ( A i^i B ) C_ x /\ x C_ A ) /\ ( ( A i^i B ) C_ B /\ B C_ B ) ) -> ( x e. CH -> x MH B ) ) | 
						
							| 31 | 19 30 | mp3an3 |  |-  ( ( A MH B /\ ( ( A i^i B ) C_ x /\ x C_ A ) ) -> ( x e. CH -> x MH B ) ) | 
						
							| 32 | 31 | imp |  |-  ( ( ( A MH B /\ ( ( A i^i B ) C_ x /\ x C_ A ) ) /\ x e. CH ) -> x MH B ) | 
						
							| 33 | 32 | an32s |  |-  ( ( ( A MH B /\ x e. CH ) /\ ( ( A i^i B ) C_ x /\ x C_ A ) ) -> x MH B ) | 
						
							| 34 | 33 | adantlll |  |-  ( ( ( ( A. c e. CH ( c MH B -> B MH* c ) /\ A MH B ) /\ x e. CH ) /\ ( ( A i^i B ) C_ x /\ x C_ A ) ) -> x MH B ) | 
						
							| 35 |  | breq1 |  |-  ( c = x -> ( c MH B <-> x MH B ) ) | 
						
							| 36 |  | breq2 |  |-  ( c = x -> ( B MH* c <-> B MH* x ) ) | 
						
							| 37 | 35 36 | imbi12d |  |-  ( c = x -> ( ( c MH B -> B MH* c ) <-> ( x MH B -> B MH* x ) ) ) | 
						
							| 38 | 37 | rspccva |  |-  ( ( A. c e. CH ( c MH B -> B MH* c ) /\ x e. CH ) -> ( x MH B -> B MH* x ) ) | 
						
							| 39 | 38 | adantlr |  |-  ( ( ( A. c e. CH ( c MH B -> B MH* c ) /\ A MH B ) /\ x e. CH ) -> ( x MH B -> B MH* x ) ) | 
						
							| 40 | 39 | adantr |  |-  ( ( ( ( A. c e. CH ( c MH B -> B MH* c ) /\ A MH B ) /\ x e. CH ) /\ ( ( A i^i B ) C_ x /\ x C_ A ) ) -> ( x MH B -> B MH* x ) ) | 
						
							| 41 | 34 40 | mpd |  |-  ( ( ( ( A. c e. CH ( c MH B -> B MH* c ) /\ A MH B ) /\ x e. CH ) /\ ( ( A i^i B ) C_ x /\ x C_ A ) ) -> B MH* x ) | 
						
							| 42 |  | simprr |  |-  ( ( ( ( A. c e. CH ( c MH B -> B MH* c ) /\ A MH B ) /\ x e. CH ) /\ ( ( A i^i B ) C_ x /\ x C_ A ) ) -> x C_ A ) | 
						
							| 43 |  | dmdi |  |-  ( ( ( B e. CH /\ x e. CH /\ A e. CH ) /\ ( B MH* x /\ x C_ A ) ) -> ( ( A i^i B ) vH x ) = ( A i^i ( B vH x ) ) ) | 
						
							| 44 | 16 41 42 43 | syl12anc |  |-  ( ( ( ( A. c e. CH ( c MH B -> B MH* c ) /\ A MH B ) /\ x e. CH ) /\ ( ( A i^i B ) C_ x /\ x C_ A ) ) -> ( ( A i^i B ) vH x ) = ( A i^i ( B vH x ) ) ) | 
						
							| 45 | 1 2 | chincli |  |-  ( A i^i B ) e. CH | 
						
							| 46 |  | chjcom |  |-  ( ( ( A i^i B ) e. CH /\ x e. CH ) -> ( ( A i^i B ) vH x ) = ( x vH ( A i^i B ) ) ) | 
						
							| 47 | 45 46 | mpan |  |-  ( x e. CH -> ( ( A i^i B ) vH x ) = ( x vH ( A i^i B ) ) ) | 
						
							| 48 | 3 | oveq2i |  |-  ( x vH ( A i^i B ) ) = ( x vH ( B i^i A ) ) | 
						
							| 49 | 47 48 | eqtrdi |  |-  ( x e. CH -> ( ( A i^i B ) vH x ) = ( x vH ( B i^i A ) ) ) | 
						
							| 50 | 49 | ad2antlr |  |-  ( ( ( ( A. c e. CH ( c MH B -> B MH* c ) /\ A MH B ) /\ x e. CH ) /\ ( ( A i^i B ) C_ x /\ x C_ A ) ) -> ( ( A i^i B ) vH x ) = ( x vH ( B i^i A ) ) ) | 
						
							| 51 | 11 44 50 | 3eqtr2d |  |-  ( ( ( ( A. c e. CH ( c MH B -> B MH* c ) /\ A MH B ) /\ x e. CH ) /\ ( ( A i^i B ) C_ x /\ x C_ A ) ) -> ( ( x vH B ) i^i A ) = ( x vH ( B i^i A ) ) ) | 
						
							| 52 | 51 | ex |  |-  ( ( ( A. c e. CH ( c MH B -> B MH* c ) /\ A MH B ) /\ x e. CH ) -> ( ( ( A i^i B ) C_ x /\ x C_ A ) -> ( ( x vH B ) i^i A ) = ( x vH ( B i^i A ) ) ) ) | 
						
							| 53 | 5 52 | sylani |  |-  ( ( ( A. c e. CH ( c MH B -> B MH* c ) /\ A MH B ) /\ x e. CH ) -> ( ( ( B i^i A ) C_ x /\ x C_ A ) -> ( ( x vH B ) i^i A ) = ( x vH ( B i^i A ) ) ) ) | 
						
							| 54 | 53 | ralrimiva |  |-  ( ( A. c e. CH ( c MH B -> B MH* c ) /\ A MH B ) -> A. x e. CH ( ( ( B i^i A ) C_ x /\ x C_ A ) -> ( ( x vH B ) i^i A ) = ( x vH ( B i^i A ) ) ) ) | 
						
							| 55 | 2 1 | mdsl2bi |  |-  ( B MH A <-> A. x e. CH ( ( ( B i^i A ) C_ x /\ x C_ A ) -> ( ( x vH B ) i^i A ) = ( x vH ( B i^i A ) ) ) ) | 
						
							| 56 | 54 55 | sylibr |  |-  ( ( A. c e. CH ( c MH B -> B MH* c ) /\ A MH B ) -> B MH A ) |