| Step | Hyp | Ref | Expression | 
						
							| 1 |  | latdisd.b |  |-  B = ( Base ` K ) | 
						
							| 2 |  | latdisd.j |  |-  .\/ = ( join ` K ) | 
						
							| 3 |  | latdisd.m |  |-  ./\ = ( meet ` K ) | 
						
							| 4 | 1 3 | latmcl |  |-  ( ( K e. Lat /\ x e. B /\ y e. B ) -> ( x ./\ y ) e. B ) | 
						
							| 5 | 4 | 3adant3r3 |  |-  ( ( K e. Lat /\ ( x e. B /\ y e. B /\ z e. B ) ) -> ( x ./\ y ) e. B ) | 
						
							| 6 |  | simpr1 |  |-  ( ( K e. Lat /\ ( x e. B /\ y e. B /\ z e. B ) ) -> x e. B ) | 
						
							| 7 |  | simpr3 |  |-  ( ( K e. Lat /\ ( x e. B /\ y e. B /\ z e. B ) ) -> z e. B ) | 
						
							| 8 |  | oveq1 |  |-  ( u = ( x ./\ y ) -> ( u .\/ ( v ./\ w ) ) = ( ( x ./\ y ) .\/ ( v ./\ w ) ) ) | 
						
							| 9 |  | oveq1 |  |-  ( u = ( x ./\ y ) -> ( u .\/ v ) = ( ( x ./\ y ) .\/ v ) ) | 
						
							| 10 |  | oveq1 |  |-  ( u = ( x ./\ y ) -> ( u .\/ w ) = ( ( x ./\ y ) .\/ w ) ) | 
						
							| 11 | 9 10 | oveq12d |  |-  ( u = ( x ./\ y ) -> ( ( u .\/ v ) ./\ ( u .\/ w ) ) = ( ( ( x ./\ y ) .\/ v ) ./\ ( ( x ./\ y ) .\/ w ) ) ) | 
						
							| 12 | 8 11 | eqeq12d |  |-  ( u = ( x ./\ y ) -> ( ( u .\/ ( v ./\ w ) ) = ( ( u .\/ v ) ./\ ( u .\/ w ) ) <-> ( ( x ./\ y ) .\/ ( v ./\ w ) ) = ( ( ( x ./\ y ) .\/ v ) ./\ ( ( x ./\ y ) .\/ w ) ) ) ) | 
						
							| 13 |  | oveq1 |  |-  ( v = x -> ( v ./\ w ) = ( x ./\ w ) ) | 
						
							| 14 | 13 | oveq2d |  |-  ( v = x -> ( ( x ./\ y ) .\/ ( v ./\ w ) ) = ( ( x ./\ y ) .\/ ( x ./\ w ) ) ) | 
						
							| 15 |  | oveq2 |  |-  ( v = x -> ( ( x ./\ y ) .\/ v ) = ( ( x ./\ y ) .\/ x ) ) | 
						
							| 16 | 15 | oveq1d |  |-  ( v = x -> ( ( ( x ./\ y ) .\/ v ) ./\ ( ( x ./\ y ) .\/ w ) ) = ( ( ( x ./\ y ) .\/ x ) ./\ ( ( x ./\ y ) .\/ w ) ) ) | 
						
							| 17 | 14 16 | eqeq12d |  |-  ( v = x -> ( ( ( x ./\ y ) .\/ ( v ./\ w ) ) = ( ( ( x ./\ y ) .\/ v ) ./\ ( ( x ./\ y ) .\/ w ) ) <-> ( ( x ./\ y ) .\/ ( x ./\ w ) ) = ( ( ( x ./\ y ) .\/ x ) ./\ ( ( x ./\ y ) .\/ w ) ) ) ) | 
						
							| 18 |  | oveq2 |  |-  ( w = z -> ( x ./\ w ) = ( x ./\ z ) ) | 
						
							| 19 | 18 | oveq2d |  |-  ( w = z -> ( ( x ./\ y ) .\/ ( x ./\ w ) ) = ( ( x ./\ y ) .\/ ( x ./\ z ) ) ) | 
						
							| 20 |  | oveq2 |  |-  ( w = z -> ( ( x ./\ y ) .\/ w ) = ( ( x ./\ y ) .\/ z ) ) | 
						
							| 21 | 20 | oveq2d |  |-  ( w = z -> ( ( ( x ./\ y ) .\/ x ) ./\ ( ( x ./\ y ) .\/ w ) ) = ( ( ( x ./\ y ) .\/ x ) ./\ ( ( x ./\ y ) .\/ z ) ) ) | 
						
							| 22 | 19 21 | eqeq12d |  |-  ( w = z -> ( ( ( x ./\ y ) .\/ ( x ./\ w ) ) = ( ( ( x ./\ y ) .\/ x ) ./\ ( ( x ./\ y ) .\/ w ) ) <-> ( ( x ./\ y ) .\/ ( x ./\ z ) ) = ( ( ( x ./\ y ) .\/ x ) ./\ ( ( x ./\ y ) .\/ z ) ) ) ) | 
						
							| 23 | 12 17 22 | rspc3v |  |-  ( ( ( x ./\ y ) e. B /\ x e. B /\ z e. B ) -> ( A. u e. B A. v e. B A. w e. B ( u .\/ ( v ./\ w ) ) = ( ( u .\/ v ) ./\ ( u .\/ w ) ) -> ( ( x ./\ y ) .\/ ( x ./\ z ) ) = ( ( ( x ./\ y ) .\/ x ) ./\ ( ( x ./\ y ) .\/ z ) ) ) ) | 
						
							| 24 | 5 6 7 23 | syl3anc |  |-  ( ( K e. Lat /\ ( x e. B /\ y e. B /\ z e. B ) ) -> ( A. u e. B A. v e. B A. w e. B ( u .\/ ( v ./\ w ) ) = ( ( u .\/ v ) ./\ ( u .\/ w ) ) -> ( ( x ./\ y ) .\/ ( x ./\ z ) ) = ( ( ( x ./\ y ) .\/ x ) ./\ ( ( x ./\ y ) .\/ z ) ) ) ) | 
						
							| 25 | 24 | imp |  |-  ( ( ( K e. Lat /\ ( x e. B /\ y e. B /\ z e. B ) ) /\ A. u e. B A. v e. B A. w e. B ( u .\/ ( v ./\ w ) ) = ( ( u .\/ v ) ./\ ( u .\/ w ) ) ) -> ( ( x ./\ y ) .\/ ( x ./\ z ) ) = ( ( ( x ./\ y ) .\/ x ) ./\ ( ( x ./\ y ) .\/ z ) ) ) | 
						
							| 26 |  | simpl |  |-  ( ( K e. Lat /\ ( x e. B /\ y e. B /\ z e. B ) ) -> K e. Lat ) | 
						
							| 27 | 1 2 | latjcom |  |-  ( ( K e. Lat /\ ( x ./\ y ) e. B /\ x e. B ) -> ( ( x ./\ y ) .\/ x ) = ( x .\/ ( x ./\ y ) ) ) | 
						
							| 28 | 26 5 6 27 | syl3anc |  |-  ( ( K e. Lat /\ ( x e. B /\ y e. B /\ z e. B ) ) -> ( ( x ./\ y ) .\/ x ) = ( x .\/ ( x ./\ y ) ) ) | 
						
							| 29 | 1 2 3 | latabs1 |  |-  ( ( K e. Lat /\ x e. B /\ y e. B ) -> ( x .\/ ( x ./\ y ) ) = x ) | 
						
							| 30 | 29 | 3adant3r3 |  |-  ( ( K e. Lat /\ ( x e. B /\ y e. B /\ z e. B ) ) -> ( x .\/ ( x ./\ y ) ) = x ) | 
						
							| 31 | 28 30 | eqtrd |  |-  ( ( K e. Lat /\ ( x e. B /\ y e. B /\ z e. B ) ) -> ( ( x ./\ y ) .\/ x ) = x ) | 
						
							| 32 | 1 2 | latjcom |  |-  ( ( K e. Lat /\ ( x ./\ y ) e. B /\ z e. B ) -> ( ( x ./\ y ) .\/ z ) = ( z .\/ ( x ./\ y ) ) ) | 
						
							| 33 | 26 5 7 32 | syl3anc |  |-  ( ( K e. Lat /\ ( x e. B /\ y e. B /\ z e. B ) ) -> ( ( x ./\ y ) .\/ z ) = ( z .\/ ( x ./\ y ) ) ) | 
						
							| 34 | 31 33 | oveq12d |  |-  ( ( K e. Lat /\ ( x e. B /\ y e. B /\ z e. B ) ) -> ( ( ( x ./\ y ) .\/ x ) ./\ ( ( x ./\ y ) .\/ z ) ) = ( x ./\ ( z .\/ ( x ./\ y ) ) ) ) | 
						
							| 35 | 34 | adantr |  |-  ( ( ( K e. Lat /\ ( x e. B /\ y e. B /\ z e. B ) ) /\ A. u e. B A. v e. B A. w e. B ( u .\/ ( v ./\ w ) ) = ( ( u .\/ v ) ./\ ( u .\/ w ) ) ) -> ( ( ( x ./\ y ) .\/ x ) ./\ ( ( x ./\ y ) .\/ z ) ) = ( x ./\ ( z .\/ ( x ./\ y ) ) ) ) | 
						
							| 36 |  | simpr2 |  |-  ( ( K e. Lat /\ ( x e. B /\ y e. B /\ z e. B ) ) -> y e. B ) | 
						
							| 37 |  | oveq1 |  |-  ( u = z -> ( u .\/ ( v ./\ w ) ) = ( z .\/ ( v ./\ w ) ) ) | 
						
							| 38 |  | oveq1 |  |-  ( u = z -> ( u .\/ v ) = ( z .\/ v ) ) | 
						
							| 39 |  | oveq1 |  |-  ( u = z -> ( u .\/ w ) = ( z .\/ w ) ) | 
						
							| 40 | 38 39 | oveq12d |  |-  ( u = z -> ( ( u .\/ v ) ./\ ( u .\/ w ) ) = ( ( z .\/ v ) ./\ ( z .\/ w ) ) ) | 
						
							| 41 | 37 40 | eqeq12d |  |-  ( u = z -> ( ( u .\/ ( v ./\ w ) ) = ( ( u .\/ v ) ./\ ( u .\/ w ) ) <-> ( z .\/ ( v ./\ w ) ) = ( ( z .\/ v ) ./\ ( z .\/ w ) ) ) ) | 
						
							| 42 | 13 | oveq2d |  |-  ( v = x -> ( z .\/ ( v ./\ w ) ) = ( z .\/ ( x ./\ w ) ) ) | 
						
							| 43 |  | oveq2 |  |-  ( v = x -> ( z .\/ v ) = ( z .\/ x ) ) | 
						
							| 44 | 43 | oveq1d |  |-  ( v = x -> ( ( z .\/ v ) ./\ ( z .\/ w ) ) = ( ( z .\/ x ) ./\ ( z .\/ w ) ) ) | 
						
							| 45 | 42 44 | eqeq12d |  |-  ( v = x -> ( ( z .\/ ( v ./\ w ) ) = ( ( z .\/ v ) ./\ ( z .\/ w ) ) <-> ( z .\/ ( x ./\ w ) ) = ( ( z .\/ x ) ./\ ( z .\/ w ) ) ) ) | 
						
							| 46 |  | oveq2 |  |-  ( w = y -> ( x ./\ w ) = ( x ./\ y ) ) | 
						
							| 47 | 46 | oveq2d |  |-  ( w = y -> ( z .\/ ( x ./\ w ) ) = ( z .\/ ( x ./\ y ) ) ) | 
						
							| 48 |  | oveq2 |  |-  ( w = y -> ( z .\/ w ) = ( z .\/ y ) ) | 
						
							| 49 | 48 | oveq2d |  |-  ( w = y -> ( ( z .\/ x ) ./\ ( z .\/ w ) ) = ( ( z .\/ x ) ./\ ( z .\/ y ) ) ) | 
						
							| 50 | 47 49 | eqeq12d |  |-  ( w = y -> ( ( z .\/ ( x ./\ w ) ) = ( ( z .\/ x ) ./\ ( z .\/ w ) ) <-> ( z .\/ ( x ./\ y ) ) = ( ( z .\/ x ) ./\ ( z .\/ y ) ) ) ) | 
						
							| 51 | 41 45 50 | rspc3v |  |-  ( ( z e. B /\ x e. B /\ y e. B ) -> ( A. u e. B A. v e. B A. w e. B ( u .\/ ( v ./\ w ) ) = ( ( u .\/ v ) ./\ ( u .\/ w ) ) -> ( z .\/ ( x ./\ y ) ) = ( ( z .\/ x ) ./\ ( z .\/ y ) ) ) ) | 
						
							| 52 | 7 6 36 51 | syl3anc |  |-  ( ( K e. Lat /\ ( x e. B /\ y e. B /\ z e. B ) ) -> ( A. u e. B A. v e. B A. w e. B ( u .\/ ( v ./\ w ) ) = ( ( u .\/ v ) ./\ ( u .\/ w ) ) -> ( z .\/ ( x ./\ y ) ) = ( ( z .\/ x ) ./\ ( z .\/ y ) ) ) ) | 
						
							| 53 | 52 | imp |  |-  ( ( ( K e. Lat /\ ( x e. B /\ y e. B /\ z e. B ) ) /\ A. u e. B A. v e. B A. w e. B ( u .\/ ( v ./\ w ) ) = ( ( u .\/ v ) ./\ ( u .\/ w ) ) ) -> ( z .\/ ( x ./\ y ) ) = ( ( z .\/ x ) ./\ ( z .\/ y ) ) ) | 
						
							| 54 | 53 | oveq2d |  |-  ( ( ( K e. Lat /\ ( x e. B /\ y e. B /\ z e. B ) ) /\ A. u e. B A. v e. B A. w e. B ( u .\/ ( v ./\ w ) ) = ( ( u .\/ v ) ./\ ( u .\/ w ) ) ) -> ( x ./\ ( z .\/ ( x ./\ y ) ) ) = ( x ./\ ( ( z .\/ x ) ./\ ( z .\/ y ) ) ) ) | 
						
							| 55 | 1 2 | latjcl |  |-  ( ( K e. Lat /\ z e. B /\ x e. B ) -> ( z .\/ x ) e. B ) | 
						
							| 56 | 26 7 6 55 | syl3anc |  |-  ( ( K e. Lat /\ ( x e. B /\ y e. B /\ z e. B ) ) -> ( z .\/ x ) e. B ) | 
						
							| 57 | 1 2 | latjcl |  |-  ( ( K e. Lat /\ z e. B /\ y e. B ) -> ( z .\/ y ) e. B ) | 
						
							| 58 | 26 7 36 57 | syl3anc |  |-  ( ( K e. Lat /\ ( x e. B /\ y e. B /\ z e. B ) ) -> ( z .\/ y ) e. B ) | 
						
							| 59 | 1 3 | latmass |  |-  ( ( K e. Lat /\ ( x e. B /\ ( z .\/ x ) e. B /\ ( z .\/ y ) e. B ) ) -> ( ( x ./\ ( z .\/ x ) ) ./\ ( z .\/ y ) ) = ( x ./\ ( ( z .\/ x ) ./\ ( z .\/ y ) ) ) ) | 
						
							| 60 | 26 6 56 58 59 | syl13anc |  |-  ( ( K e. Lat /\ ( x e. B /\ y e. B /\ z e. B ) ) -> ( ( x ./\ ( z .\/ x ) ) ./\ ( z .\/ y ) ) = ( x ./\ ( ( z .\/ x ) ./\ ( z .\/ y ) ) ) ) | 
						
							| 61 | 1 2 | latjcom |  |-  ( ( K e. Lat /\ z e. B /\ x e. B ) -> ( z .\/ x ) = ( x .\/ z ) ) | 
						
							| 62 | 26 7 6 61 | syl3anc |  |-  ( ( K e. Lat /\ ( x e. B /\ y e. B /\ z e. B ) ) -> ( z .\/ x ) = ( x .\/ z ) ) | 
						
							| 63 | 62 | oveq2d |  |-  ( ( K e. Lat /\ ( x e. B /\ y e. B /\ z e. B ) ) -> ( x ./\ ( z .\/ x ) ) = ( x ./\ ( x .\/ z ) ) ) | 
						
							| 64 | 1 2 3 | latabs2 |  |-  ( ( K e. Lat /\ x e. B /\ z e. B ) -> ( x ./\ ( x .\/ z ) ) = x ) | 
						
							| 65 | 26 6 7 64 | syl3anc |  |-  ( ( K e. Lat /\ ( x e. B /\ y e. B /\ z e. B ) ) -> ( x ./\ ( x .\/ z ) ) = x ) | 
						
							| 66 | 63 65 | eqtrd |  |-  ( ( K e. Lat /\ ( x e. B /\ y e. B /\ z e. B ) ) -> ( x ./\ ( z .\/ x ) ) = x ) | 
						
							| 67 | 1 2 | latjcom |  |-  ( ( K e. Lat /\ z e. B /\ y e. B ) -> ( z .\/ y ) = ( y .\/ z ) ) | 
						
							| 68 | 26 7 36 67 | syl3anc |  |-  ( ( K e. Lat /\ ( x e. B /\ y e. B /\ z e. B ) ) -> ( z .\/ y ) = ( y .\/ z ) ) | 
						
							| 69 | 66 68 | oveq12d |  |-  ( ( K e. Lat /\ ( x e. B /\ y e. B /\ z e. B ) ) -> ( ( x ./\ ( z .\/ x ) ) ./\ ( z .\/ y ) ) = ( x ./\ ( y .\/ z ) ) ) | 
						
							| 70 | 60 69 | eqtr3d |  |-  ( ( K e. Lat /\ ( x e. B /\ y e. B /\ z e. B ) ) -> ( x ./\ ( ( z .\/ x ) ./\ ( z .\/ y ) ) ) = ( x ./\ ( y .\/ z ) ) ) | 
						
							| 71 | 70 | adantr |  |-  ( ( ( K e. Lat /\ ( x e. B /\ y e. B /\ z e. B ) ) /\ A. u e. B A. v e. B A. w e. B ( u .\/ ( v ./\ w ) ) = ( ( u .\/ v ) ./\ ( u .\/ w ) ) ) -> ( x ./\ ( ( z .\/ x ) ./\ ( z .\/ y ) ) ) = ( x ./\ ( y .\/ z ) ) ) | 
						
							| 72 | 54 71 | eqtrd |  |-  ( ( ( K e. Lat /\ ( x e. B /\ y e. B /\ z e. B ) ) /\ A. u e. B A. v e. B A. w e. B ( u .\/ ( v ./\ w ) ) = ( ( u .\/ v ) ./\ ( u .\/ w ) ) ) -> ( x ./\ ( z .\/ ( x ./\ y ) ) ) = ( x ./\ ( y .\/ z ) ) ) | 
						
							| 73 | 25 35 72 | 3eqtrrd |  |-  ( ( ( K e. Lat /\ ( x e. B /\ y e. B /\ z e. B ) ) /\ A. u e. B A. v e. B A. w e. B ( u .\/ ( v ./\ w ) ) = ( ( u .\/ v ) ./\ ( u .\/ w ) ) ) -> ( x ./\ ( y .\/ z ) ) = ( ( x ./\ y ) .\/ ( x ./\ z ) ) ) | 
						
							| 74 | 73 | an32s |  |-  ( ( ( K e. Lat /\ A. u e. B A. v e. B A. w e. B ( u .\/ ( v ./\ w ) ) = ( ( u .\/ v ) ./\ ( u .\/ w ) ) ) /\ ( x e. B /\ y e. B /\ z e. B ) ) -> ( x ./\ ( y .\/ z ) ) = ( ( x ./\ y ) .\/ ( x ./\ z ) ) ) | 
						
							| 75 | 74 | ralrimivvva |  |-  ( ( 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 ) ) ) | 
						
							| 76 | 75 | ex |  |-  ( 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 ) ) ) ) |