| Step | Hyp | Ref | Expression | 
						
							| 1 |  | latdisd.b |  |-  B = ( Base ` K ) | 
						
							| 2 |  | latdisd.j |  |-  .\/ = ( join ` K ) | 
						
							| 3 |  | latdisd.m |  |-  ./\ = ( meet ` K ) | 
						
							| 4 | 1 2 3 | latdisdlem |  |-  ( K e. Lat -> ( A. x e. B A. y e. B A. z e. B ( x .\/ ( y ./\ z ) ) = ( ( x .\/ y ) ./\ ( x .\/ z ) ) -> A. u e. B A. v e. B A. w e. B ( u ./\ ( v .\/ w ) ) = ( ( u ./\ v ) .\/ ( u ./\ w ) ) ) ) | 
						
							| 5 |  | eqid |  |-  ( ODual ` K ) = ( ODual ` K ) | 
						
							| 6 | 5 | odulat |  |-  ( K e. Lat -> ( ODual ` K ) e. Lat ) | 
						
							| 7 | 5 1 | odubas |  |-  B = ( Base ` ( ODual ` K ) ) | 
						
							| 8 | 5 3 | odujoin |  |-  ./\ = ( join ` ( ODual ` K ) ) | 
						
							| 9 | 5 2 | odumeet |  |-  .\/ = ( meet ` ( ODual ` K ) ) | 
						
							| 10 | 7 8 9 | latdisdlem |  |-  ( ( ODual ` K ) e. Lat -> ( A. u e. B A. v e. B A. w e. B ( u ./\ ( v .\/ w ) ) = ( ( u ./\ v ) .\/ ( u ./\ w ) ) -> A. x e. B A. y e. B A. z e. B ( x .\/ ( y ./\ z ) ) = ( ( x .\/ y ) ./\ ( x .\/ z ) ) ) ) | 
						
							| 11 | 6 10 | syl |  |-  ( K e. Lat -> ( A. u e. B A. v e. B A. w e. B ( u ./\ ( v .\/ w ) ) = ( ( u ./\ v ) .\/ ( u ./\ w ) ) -> A. x e. B A. y e. B A. z e. B ( x .\/ ( y ./\ z ) ) = ( ( x .\/ y ) ./\ ( x .\/ z ) ) ) ) | 
						
							| 12 | 4 11 | impbid |  |-  ( K e. Lat -> ( A. x e. B A. y e. B A. z e. B ( x .\/ ( y ./\ z ) ) = ( ( x .\/ y ) ./\ ( x .\/ z ) ) <-> A. u e. B A. v e. B A. w e. B ( u ./\ ( v .\/ w ) ) = ( ( u ./\ v ) .\/ ( u ./\ w ) ) ) ) | 
						
							| 13 |  | oveq1 |  |-  ( u = x -> ( u ./\ ( v .\/ w ) ) = ( x ./\ ( v .\/ w ) ) ) | 
						
							| 14 |  | oveq1 |  |-  ( u = x -> ( u ./\ v ) = ( x ./\ v ) ) | 
						
							| 15 |  | oveq1 |  |-  ( u = x -> ( u ./\ w ) = ( x ./\ w ) ) | 
						
							| 16 | 14 15 | oveq12d |  |-  ( u = x -> ( ( u ./\ v ) .\/ ( u ./\ w ) ) = ( ( x ./\ v ) .\/ ( x ./\ w ) ) ) | 
						
							| 17 | 13 16 | eqeq12d |  |-  ( u = x -> ( ( u ./\ ( v .\/ w ) ) = ( ( u ./\ v ) .\/ ( u ./\ w ) ) <-> ( x ./\ ( v .\/ w ) ) = ( ( x ./\ v ) .\/ ( x ./\ w ) ) ) ) | 
						
							| 18 |  | oveq1 |  |-  ( v = y -> ( v .\/ w ) = ( y .\/ w ) ) | 
						
							| 19 | 18 | oveq2d |  |-  ( v = y -> ( x ./\ ( v .\/ w ) ) = ( x ./\ ( y .\/ w ) ) ) | 
						
							| 20 |  | oveq2 |  |-  ( v = y -> ( x ./\ v ) = ( x ./\ y ) ) | 
						
							| 21 | 20 | oveq1d |  |-  ( v = y -> ( ( x ./\ v ) .\/ ( x ./\ w ) ) = ( ( x ./\ y ) .\/ ( x ./\ w ) ) ) | 
						
							| 22 | 19 21 | eqeq12d |  |-  ( v = y -> ( ( x ./\ ( v .\/ w ) ) = ( ( x ./\ v ) .\/ ( x ./\ w ) ) <-> ( x ./\ ( y .\/ w ) ) = ( ( x ./\ y ) .\/ ( x ./\ w ) ) ) ) | 
						
							| 23 |  | oveq2 |  |-  ( w = z -> ( y .\/ w ) = ( y .\/ z ) ) | 
						
							| 24 | 23 | oveq2d |  |-  ( w = z -> ( x ./\ ( y .\/ w ) ) = ( x ./\ ( y .\/ z ) ) ) | 
						
							| 25 |  | oveq2 |  |-  ( w = z -> ( x ./\ w ) = ( x ./\ z ) ) | 
						
							| 26 | 25 | oveq2d |  |-  ( w = z -> ( ( x ./\ y ) .\/ ( x ./\ w ) ) = ( ( x ./\ y ) .\/ ( x ./\ z ) ) ) | 
						
							| 27 | 24 26 | eqeq12d |  |-  ( w = z -> ( ( x ./\ ( y .\/ w ) ) = ( ( x ./\ y ) .\/ ( x ./\ w ) ) <-> ( x ./\ ( y .\/ z ) ) = ( ( x ./\ y ) .\/ ( x ./\ z ) ) ) ) | 
						
							| 28 | 17 22 27 | cbvral3vw |  |-  ( A. u e. B A. v e. B A. w e. B ( u ./\ ( v .\/ w ) ) = ( ( u ./\ v ) .\/ ( u ./\ w ) ) <-> A. x e. B A. y e. B A. z e. B ( x ./\ ( y .\/ z ) ) = ( ( x ./\ y ) .\/ ( x ./\ z ) ) ) | 
						
							| 29 | 12 28 | bitrdi |  |-  ( K e. Lat -> ( A. x e. B A. y e. B A. z e. B ( x .\/ ( y ./\ z ) ) = ( ( x .\/ y ) ./\ ( x .\/ z ) ) <-> A. x e. B A. y e. B A. z e. B ( x ./\ ( y .\/ z ) ) = ( ( x ./\ y ) .\/ ( x ./\ z ) ) ) ) |