| Step | Hyp | Ref | Expression | 
						
							| 1 |  | 4at.l |  |-  .<_ = ( le ` K ) | 
						
							| 2 |  | 4at.j |  |-  .\/ = ( join ` K ) | 
						
							| 3 |  | 4at.a |  |-  A = ( Atoms ` K ) | 
						
							| 4 | 1 2 3 | 4atlem12 |  |-  ( ( ( ( K e. HL /\ P e. A /\ Q e. A ) /\ ( R e. A /\ S e. A /\ T e. A ) /\ ( U e. A /\ V e. A /\ W e. A ) ) /\ ( P =/= Q /\ -. R .<_ ( P .\/ Q ) /\ -. S .<_ ( ( P .\/ Q ) .\/ R ) ) ) -> ( ( ( P .\/ Q ) .\/ ( R .\/ S ) ) .<_ ( ( T .\/ U ) .\/ ( V .\/ W ) ) -> ( ( P .\/ Q ) .\/ ( R .\/ S ) ) = ( ( T .\/ U ) .\/ ( V .\/ W ) ) ) ) | 
						
							| 5 |  | simp11 |  |-  ( ( ( K e. HL /\ P e. A /\ Q e. A ) /\ ( R e. A /\ S e. A /\ T e. A ) /\ ( U e. A /\ V e. A /\ W e. A ) ) -> K e. HL ) | 
						
							| 6 | 5 | hllatd |  |-  ( ( ( K e. HL /\ P e. A /\ Q e. A ) /\ ( R e. A /\ S e. A /\ T e. A ) /\ ( U e. A /\ V e. A /\ W e. A ) ) -> K e. Lat ) | 
						
							| 7 |  | simp23 |  |-  ( ( ( K e. HL /\ P e. A /\ Q e. A ) /\ ( R e. A /\ S e. A /\ T e. A ) /\ ( U e. A /\ V e. A /\ W e. A ) ) -> T e. A ) | 
						
							| 8 |  | simp31 |  |-  ( ( ( K e. HL /\ P e. A /\ Q e. A ) /\ ( R e. A /\ S e. A /\ T e. A ) /\ ( U e. A /\ V e. A /\ W e. A ) ) -> U e. A ) | 
						
							| 9 |  | eqid |  |-  ( Base ` K ) = ( Base ` K ) | 
						
							| 10 | 9 2 3 | hlatjcl |  |-  ( ( K e. HL /\ T e. A /\ U e. A ) -> ( T .\/ U ) e. ( Base ` K ) ) | 
						
							| 11 | 5 7 8 10 | syl3anc |  |-  ( ( ( K e. HL /\ P e. A /\ Q e. A ) /\ ( R e. A /\ S e. A /\ T e. A ) /\ ( U e. A /\ V e. A /\ W e. A ) ) -> ( T .\/ U ) e. ( Base ` K ) ) | 
						
							| 12 |  | simp32 |  |-  ( ( ( K e. HL /\ P e. A /\ Q e. A ) /\ ( R e. A /\ S e. A /\ T e. A ) /\ ( U e. A /\ V e. A /\ W e. A ) ) -> V e. A ) | 
						
							| 13 |  | simp33 |  |-  ( ( ( K e. HL /\ P e. A /\ Q e. A ) /\ ( R e. A /\ S e. A /\ T e. A ) /\ ( U e. A /\ V e. A /\ W e. A ) ) -> W e. A ) | 
						
							| 14 | 9 2 3 | hlatjcl |  |-  ( ( K e. HL /\ V e. A /\ W e. A ) -> ( V .\/ W ) e. ( Base ` K ) ) | 
						
							| 15 | 5 12 13 14 | syl3anc |  |-  ( ( ( K e. HL /\ P e. A /\ Q e. A ) /\ ( R e. A /\ S e. A /\ T e. A ) /\ ( U e. A /\ V e. A /\ W e. A ) ) -> ( V .\/ W ) e. ( Base ` K ) ) | 
						
							| 16 | 9 2 | latjcl |  |-  ( ( K e. Lat /\ ( T .\/ U ) e. ( Base ` K ) /\ ( V .\/ W ) e. ( Base ` K ) ) -> ( ( T .\/ U ) .\/ ( V .\/ W ) ) e. ( Base ` K ) ) | 
						
							| 17 | 6 11 15 16 | syl3anc |  |-  ( ( ( K e. HL /\ P e. A /\ Q e. A ) /\ ( R e. A /\ S e. A /\ T e. A ) /\ ( U e. A /\ V e. A /\ W e. A ) ) -> ( ( T .\/ U ) .\/ ( V .\/ W ) ) e. ( Base ` K ) ) | 
						
							| 18 | 9 1 | latref |  |-  ( ( K e. Lat /\ ( ( T .\/ U ) .\/ ( V .\/ W ) ) e. ( Base ` K ) ) -> ( ( T .\/ U ) .\/ ( V .\/ W ) ) .<_ ( ( T .\/ U ) .\/ ( V .\/ W ) ) ) | 
						
							| 19 | 6 17 18 | syl2anc |  |-  ( ( ( K e. HL /\ P e. A /\ Q e. A ) /\ ( R e. A /\ S e. A /\ T e. A ) /\ ( U e. A /\ V e. A /\ W e. A ) ) -> ( ( T .\/ U ) .\/ ( V .\/ W ) ) .<_ ( ( T .\/ U ) .\/ ( V .\/ W ) ) ) | 
						
							| 20 |  | breq1 |  |-  ( ( ( P .\/ Q ) .\/ ( R .\/ S ) ) = ( ( T .\/ U ) .\/ ( V .\/ W ) ) -> ( ( ( P .\/ Q ) .\/ ( R .\/ S ) ) .<_ ( ( T .\/ U ) .\/ ( V .\/ W ) ) <-> ( ( T .\/ U ) .\/ ( V .\/ W ) ) .<_ ( ( T .\/ U ) .\/ ( V .\/ W ) ) ) ) | 
						
							| 21 | 19 20 | syl5ibrcom |  |-  ( ( ( K e. HL /\ P e. A /\ Q e. A ) /\ ( R e. A /\ S e. A /\ T e. A ) /\ ( U e. A /\ V e. A /\ W e. A ) ) -> ( ( ( P .\/ Q ) .\/ ( R .\/ S ) ) = ( ( T .\/ U ) .\/ ( V .\/ W ) ) -> ( ( P .\/ Q ) .\/ ( R .\/ S ) ) .<_ ( ( T .\/ U ) .\/ ( V .\/ W ) ) ) ) | 
						
							| 22 | 21 | adantr |  |-  ( ( ( ( K e. HL /\ P e. A /\ Q e. A ) /\ ( R e. A /\ S e. A /\ T e. A ) /\ ( U e. A /\ V e. A /\ W e. A ) ) /\ ( P =/= Q /\ -. R .<_ ( P .\/ Q ) /\ -. S .<_ ( ( P .\/ Q ) .\/ R ) ) ) -> ( ( ( P .\/ Q ) .\/ ( R .\/ S ) ) = ( ( T .\/ U ) .\/ ( V .\/ W ) ) -> ( ( P .\/ Q ) .\/ ( R .\/ S ) ) .<_ ( ( T .\/ U ) .\/ ( V .\/ W ) ) ) ) | 
						
							| 23 | 4 22 | impbid |  |-  ( ( ( ( K e. HL /\ P e. A /\ Q e. A ) /\ ( R e. A /\ S e. A /\ T e. A ) /\ ( U e. A /\ V e. A /\ W e. A ) ) /\ ( P =/= Q /\ -. R .<_ ( P .\/ Q ) /\ -. S .<_ ( ( P .\/ Q ) .\/ R ) ) ) -> ( ( ( P .\/ Q ) .\/ ( R .\/ S ) ) .<_ ( ( T .\/ U ) .\/ ( V .\/ W ) ) <-> ( ( P .\/ Q ) .\/ ( R .\/ S ) ) = ( ( T .\/ U ) .\/ ( V .\/ W ) ) ) ) |