| Step | 
						Hyp | 
						Ref | 
						Expression | 
					
						
							| 1 | 
							
								
							 | 
							4thatlem.ph | 
							⊢ ( 𝜑  ↔  ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑃  ∈  𝐴  ∧  ¬  𝑃  ≤  𝑊 )  ∧  ( 𝑄  ∈  𝐴  ∧  ¬  𝑄  ≤  𝑊 ) )  ∧  ( 𝑆  ∈  𝐴  ∧  ( 𝑅  ∈  𝐴  ∧  ¬  𝑅  ≤  𝑊  ∧  ( 𝑃  ∨  𝑅 )  =  ( 𝑄  ∨  𝑅 ) )  ∧  ( 𝑇  ∈  𝐴  ∧  ( 𝑈  ∨  𝑇 )  =  ( 𝑉  ∨  𝑇 ) ) )  ∧  ( 𝑃  ≠  𝑄  ∧  ¬  𝑆  ≤  ( 𝑃  ∨  𝑄 ) ) ) )  | 
						
						
							| 2 | 
							
								
							 | 
							4thatlem0.l | 
							⊢  ≤   =  ( le ‘ 𝐾 )  | 
						
						
							| 3 | 
							
								
							 | 
							4thatlem0.j | 
							⊢  ∨   =  ( join ‘ 𝐾 )  | 
						
						
							| 4 | 
							
								
							 | 
							4thatlem0.m | 
							⊢  ∧   =  ( meet ‘ 𝐾 )  | 
						
						
							| 5 | 
							
								
							 | 
							4thatlem0.a | 
							⊢ 𝐴  =  ( Atoms ‘ 𝐾 )  | 
						
						
							| 6 | 
							
								
							 | 
							4thatlem0.h | 
							⊢ 𝐻  =  ( LHyp ‘ 𝐾 )  | 
						
						
							| 7 | 
							
								
							 | 
							4thatlem0.u | 
							⊢ 𝑈  =  ( ( 𝑃  ∨  𝑄 )  ∧  𝑊 )  | 
						
						
							| 8 | 
							
								
							 | 
							4thatlem0.v | 
							⊢ 𝑉  =  ( ( 𝑃  ∨  𝑆 )  ∧  𝑊 )  | 
						
						
							| 9 | 
							
								
							 | 
							4thatlem0.c | 
							⊢ 𝐶  =  ( ( 𝑄  ∨  𝑇 )  ∧  ( 𝑃  ∨  𝑆 ) )  | 
						
						
							| 10 | 
							
								
							 | 
							4thatlem0.d | 
							⊢ 𝐷  =  ( ( 𝑅  ∨  𝑇 )  ∧  ( 𝑃  ∨  𝑆 ) )  | 
						
						
							| 11 | 
							
								1 2 3 4 5 6 7 8
							 | 
							4atexlemtlw | 
							⊢ ( 𝜑  →  𝑇  ≤  𝑊 )  | 
						
						
							| 12 | 
							
								1 2 3 4 5 6 7 8 9
							 | 
							4atexlemnclw | 
							⊢ ( 𝜑  →  ¬  𝐶  ≤  𝑊 )  | 
						
						
							| 13 | 
							
								
							 | 
							nbrne2 | 
							⊢ ( ( 𝑇  ≤  𝑊  ∧  ¬  𝐶  ≤  𝑊 )  →  𝑇  ≠  𝐶 )  | 
						
						
							| 14 | 
							
								11 12 13
							 | 
							syl2anc | 
							⊢ ( 𝜑  →  𝑇  ≠  𝐶 )  | 
						
						
							| 15 | 
							
								1
							 | 
							4atexlemk | 
							⊢ ( 𝜑  →  𝐾  ∈  HL )  | 
						
						
							| 16 | 
							
								1
							 | 
							4atexlemq | 
							⊢ ( 𝜑  →  𝑄  ∈  𝐴 )  | 
						
						
							| 17 | 
							
								1
							 | 
							4atexlemt | 
							⊢ ( 𝜑  →  𝑇  ∈  𝐴 )  | 
						
						
							| 18 | 
							
								3 5
							 | 
							hlatjcom | 
							⊢ ( ( 𝐾  ∈  HL  ∧  𝑄  ∈  𝐴  ∧  𝑇  ∈  𝐴 )  →  ( 𝑄  ∨  𝑇 )  =  ( 𝑇  ∨  𝑄 ) )  | 
						
						
							| 19 | 
							
								15 16 17 18
							 | 
							syl3anc | 
							⊢ ( 𝜑  →  ( 𝑄  ∨  𝑇 )  =  ( 𝑇  ∨  𝑄 ) )  | 
						
						
							| 20 | 
							
								
							 | 
							simp221 | 
							⊢ ( ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑃  ∈  𝐴  ∧  ¬  𝑃  ≤  𝑊 )  ∧  ( 𝑄  ∈  𝐴  ∧  ¬  𝑄  ≤  𝑊 ) )  ∧  ( 𝑆  ∈  𝐴  ∧  ( 𝑅  ∈  𝐴  ∧  ¬  𝑅  ≤  𝑊  ∧  ( 𝑃  ∨  𝑅 )  =  ( 𝑄  ∨  𝑅 ) )  ∧  ( 𝑇  ∈  𝐴  ∧  ( 𝑈  ∨  𝑇 )  =  ( 𝑉  ∨  𝑇 ) ) )  ∧  ( 𝑃  ≠  𝑄  ∧  ¬  𝑆  ≤  ( 𝑃  ∨  𝑄 ) ) )  →  𝑅  ∈  𝐴 )  | 
						
						
							| 21 | 
							
								1 20
							 | 
							sylbi | 
							⊢ ( 𝜑  →  𝑅  ∈  𝐴 )  | 
						
						
							| 22 | 
							
								3 5
							 | 
							hlatjcom | 
							⊢ ( ( 𝐾  ∈  HL  ∧  𝑅  ∈  𝐴  ∧  𝑇  ∈  𝐴 )  →  ( 𝑅  ∨  𝑇 )  =  ( 𝑇  ∨  𝑅 ) )  | 
						
						
							| 23 | 
							
								15 21 17 22
							 | 
							syl3anc | 
							⊢ ( 𝜑  →  ( 𝑅  ∨  𝑇 )  =  ( 𝑇  ∨  𝑅 ) )  | 
						
						
							| 24 | 
							
								19 23
							 | 
							oveq12d | 
							⊢ ( 𝜑  →  ( ( 𝑄  ∨  𝑇 )  ∧  ( 𝑅  ∨  𝑇 ) )  =  ( ( 𝑇  ∨  𝑄 )  ∧  ( 𝑇  ∨  𝑅 ) ) )  | 
						
						
							| 25 | 
							
								1
							 | 
							4atexlemkc | 
							⊢ ( 𝜑  →  𝐾  ∈  CvLat )  | 
						
						
							| 26 | 
							
								1
							 | 
							4atexlemp | 
							⊢ ( 𝜑  →  𝑃  ∈  𝐴 )  | 
						
						
							| 27 | 
							
								1
							 | 
							4atexlempnq | 
							⊢ ( 𝜑  →  𝑃  ≠  𝑄 )  | 
						
						
							| 28 | 
							
								
							 | 
							simp223 | 
							⊢ ( ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑃  ∈  𝐴  ∧  ¬  𝑃  ≤  𝑊 )  ∧  ( 𝑄  ∈  𝐴  ∧  ¬  𝑄  ≤  𝑊 ) )  ∧  ( 𝑆  ∈  𝐴  ∧  ( 𝑅  ∈  𝐴  ∧  ¬  𝑅  ≤  𝑊  ∧  ( 𝑃  ∨  𝑅 )  =  ( 𝑄  ∨  𝑅 ) )  ∧  ( 𝑇  ∈  𝐴  ∧  ( 𝑈  ∨  𝑇 )  =  ( 𝑉  ∨  𝑇 ) ) )  ∧  ( 𝑃  ≠  𝑄  ∧  ¬  𝑆  ≤  ( 𝑃  ∨  𝑄 ) ) )  →  ( 𝑃  ∨  𝑅 )  =  ( 𝑄  ∨  𝑅 ) )  | 
						
						
							| 29 | 
							
								1 28
							 | 
							sylbi | 
							⊢ ( 𝜑  →  ( 𝑃  ∨  𝑅 )  =  ( 𝑄  ∨  𝑅 ) )  | 
						
						
							| 30 | 
							
								5 3
							 | 
							cvlsupr6 | 
							⊢ ( ( 𝐾  ∈  CvLat  ∧  ( 𝑃  ∈  𝐴  ∧  𝑄  ∈  𝐴  ∧  𝑅  ∈  𝐴 )  ∧  ( 𝑃  ≠  𝑄  ∧  ( 𝑃  ∨  𝑅 )  =  ( 𝑄  ∨  𝑅 ) ) )  →  𝑅  ≠  𝑄 )  | 
						
						
							| 31 | 
							
								30
							 | 
							necomd | 
							⊢ ( ( 𝐾  ∈  CvLat  ∧  ( 𝑃  ∈  𝐴  ∧  𝑄  ∈  𝐴  ∧  𝑅  ∈  𝐴 )  ∧  ( 𝑃  ≠  𝑄  ∧  ( 𝑃  ∨  𝑅 )  =  ( 𝑄  ∨  𝑅 ) ) )  →  𝑄  ≠  𝑅 )  | 
						
						
							| 32 | 
							
								25 26 16 21 27 29 31
							 | 
							syl132anc | 
							⊢ ( 𝜑  →  𝑄  ≠  𝑅 )  | 
						
						
							| 33 | 
							
								1 2 3 4 5 6 7 8
							 | 
							4atexlemntlpq | 
							⊢ ( 𝜑  →  ¬  𝑇  ≤  ( 𝑃  ∨  𝑄 ) )  | 
						
						
							| 34 | 
							
								5 3
							 | 
							cvlsupr7 | 
							⊢ ( ( 𝐾  ∈  CvLat  ∧  ( 𝑃  ∈  𝐴  ∧  𝑄  ∈  𝐴  ∧  𝑅  ∈  𝐴 )  ∧  ( 𝑃  ≠  𝑄  ∧  ( 𝑃  ∨  𝑅 )  =  ( 𝑄  ∨  𝑅 ) ) )  →  ( 𝑃  ∨  𝑄 )  =  ( 𝑅  ∨  𝑄 ) )  | 
						
						
							| 35 | 
							
								25 26 16 21 27 29 34
							 | 
							syl132anc | 
							⊢ ( 𝜑  →  ( 𝑃  ∨  𝑄 )  =  ( 𝑅  ∨  𝑄 ) )  | 
						
						
							| 36 | 
							
								3 5
							 | 
							hlatjcom | 
							⊢ ( ( 𝐾  ∈  HL  ∧  𝑄  ∈  𝐴  ∧  𝑅  ∈  𝐴 )  →  ( 𝑄  ∨  𝑅 )  =  ( 𝑅  ∨  𝑄 ) )  | 
						
						
							| 37 | 
							
								15 16 21 36
							 | 
							syl3anc | 
							⊢ ( 𝜑  →  ( 𝑄  ∨  𝑅 )  =  ( 𝑅  ∨  𝑄 ) )  | 
						
						
							| 38 | 
							
								35 37
							 | 
							eqtr4d | 
							⊢ ( 𝜑  →  ( 𝑃  ∨  𝑄 )  =  ( 𝑄  ∨  𝑅 ) )  | 
						
						
							| 39 | 
							
								38
							 | 
							breq2d | 
							⊢ ( 𝜑  →  ( 𝑇  ≤  ( 𝑃  ∨  𝑄 )  ↔  𝑇  ≤  ( 𝑄  ∨  𝑅 ) ) )  | 
						
						
							| 40 | 
							
								33 39
							 | 
							mtbid | 
							⊢ ( 𝜑  →  ¬  𝑇  ≤  ( 𝑄  ∨  𝑅 ) )  | 
						
						
							| 41 | 
							
								2 3 4 5
							 | 
							2llnma2 | 
							⊢ ( ( 𝐾  ∈  HL  ∧  ( 𝑄  ∈  𝐴  ∧  𝑅  ∈  𝐴  ∧  𝑇  ∈  𝐴 )  ∧  ( 𝑄  ≠  𝑅  ∧  ¬  𝑇  ≤  ( 𝑄  ∨  𝑅 ) ) )  →  ( ( 𝑇  ∨  𝑄 )  ∧  ( 𝑇  ∨  𝑅 ) )  =  𝑇 )  | 
						
						
							| 42 | 
							
								15 16 21 17 32 40 41
							 | 
							syl132anc | 
							⊢ ( 𝜑  →  ( ( 𝑇  ∨  𝑄 )  ∧  ( 𝑇  ∨  𝑅 ) )  =  𝑇 )  | 
						
						
							| 43 | 
							
								24 42
							 | 
							eqtr2d | 
							⊢ ( 𝜑  →  𝑇  =  ( ( 𝑄  ∨  𝑇 )  ∧  ( 𝑅  ∨  𝑇 ) ) )  | 
						
						
							| 44 | 
							
								43
							 | 
							adantr | 
							⊢ ( ( 𝜑  ∧  𝐶  =  𝐷 )  →  𝑇  =  ( ( 𝑄  ∨  𝑇 )  ∧  ( 𝑅  ∨  𝑇 ) ) )  | 
						
						
							| 45 | 
							
								1
							 | 
							4atexlemkl | 
							⊢ ( 𝜑  →  𝐾  ∈  Lat )  | 
						
						
							| 46 | 
							
								1 3 5
							 | 
							4atexlemqtb | 
							⊢ ( 𝜑  →  ( 𝑄  ∨  𝑇 )  ∈  ( Base ‘ 𝐾 ) )  | 
						
						
							| 47 | 
							
								1 3 5
							 | 
							4atexlempsb | 
							⊢ ( 𝜑  →  ( 𝑃  ∨  𝑆 )  ∈  ( Base ‘ 𝐾 ) )  | 
						
						
							| 48 | 
							
								
							 | 
							eqid | 
							⊢ ( Base ‘ 𝐾 )  =  ( Base ‘ 𝐾 )  | 
						
						
							| 49 | 
							
								48 2 4
							 | 
							latmle1 | 
							⊢ ( ( 𝐾  ∈  Lat  ∧  ( 𝑄  ∨  𝑇 )  ∈  ( Base ‘ 𝐾 )  ∧  ( 𝑃  ∨  𝑆 )  ∈  ( Base ‘ 𝐾 ) )  →  ( ( 𝑄  ∨  𝑇 )  ∧  ( 𝑃  ∨  𝑆 ) )  ≤  ( 𝑄  ∨  𝑇 ) )  | 
						
						
							| 50 | 
							
								45 46 47 49
							 | 
							syl3anc | 
							⊢ ( 𝜑  →  ( ( 𝑄  ∨  𝑇 )  ∧  ( 𝑃  ∨  𝑆 ) )  ≤  ( 𝑄  ∨  𝑇 ) )  | 
						
						
							| 51 | 
							
								9 50
							 | 
							eqbrtrid | 
							⊢ ( 𝜑  →  𝐶  ≤  ( 𝑄  ∨  𝑇 ) )  | 
						
						
							| 52 | 
							
								51
							 | 
							adantr | 
							⊢ ( ( 𝜑  ∧  𝐶  =  𝐷 )  →  𝐶  ≤  ( 𝑄  ∨  𝑇 ) )  | 
						
						
							| 53 | 
							
								
							 | 
							simpr | 
							⊢ ( ( 𝜑  ∧  𝐶  =  𝐷 )  →  𝐶  =  𝐷 )  | 
						
						
							| 54 | 
							
								48 3 5
							 | 
							hlatjcl | 
							⊢ ( ( 𝐾  ∈  HL  ∧  𝑅  ∈  𝐴  ∧  𝑇  ∈  𝐴 )  →  ( 𝑅  ∨  𝑇 )  ∈  ( Base ‘ 𝐾 ) )  | 
						
						
							| 55 | 
							
								15 21 17 54
							 | 
							syl3anc | 
							⊢ ( 𝜑  →  ( 𝑅  ∨  𝑇 )  ∈  ( Base ‘ 𝐾 ) )  | 
						
						
							| 56 | 
							
								48 2 4
							 | 
							latmle1 | 
							⊢ ( ( 𝐾  ∈  Lat  ∧  ( 𝑅  ∨  𝑇 )  ∈  ( Base ‘ 𝐾 )  ∧  ( 𝑃  ∨  𝑆 )  ∈  ( Base ‘ 𝐾 ) )  →  ( ( 𝑅  ∨  𝑇 )  ∧  ( 𝑃  ∨  𝑆 ) )  ≤  ( 𝑅  ∨  𝑇 ) )  | 
						
						
							| 57 | 
							
								45 55 47 56
							 | 
							syl3anc | 
							⊢ ( 𝜑  →  ( ( 𝑅  ∨  𝑇 )  ∧  ( 𝑃  ∨  𝑆 ) )  ≤  ( 𝑅  ∨  𝑇 ) )  | 
						
						
							| 58 | 
							
								10 57
							 | 
							eqbrtrid | 
							⊢ ( 𝜑  →  𝐷  ≤  ( 𝑅  ∨  𝑇 ) )  | 
						
						
							| 59 | 
							
								58
							 | 
							adantr | 
							⊢ ( ( 𝜑  ∧  𝐶  =  𝐷 )  →  𝐷  ≤  ( 𝑅  ∨  𝑇 ) )  | 
						
						
							| 60 | 
							
								53 59
							 | 
							eqbrtrd | 
							⊢ ( ( 𝜑  ∧  𝐶  =  𝐷 )  →  𝐶  ≤  ( 𝑅  ∨  𝑇 ) )  | 
						
						
							| 61 | 
							
								1 2 3 4 5 6 7 8 9
							 | 
							4atexlemc | 
							⊢ ( 𝜑  →  𝐶  ∈  𝐴 )  | 
						
						
							| 62 | 
							
								48 5
							 | 
							atbase | 
							⊢ ( 𝐶  ∈  𝐴  →  𝐶  ∈  ( Base ‘ 𝐾 ) )  | 
						
						
							| 63 | 
							
								61 62
							 | 
							syl | 
							⊢ ( 𝜑  →  𝐶  ∈  ( Base ‘ 𝐾 ) )  | 
						
						
							| 64 | 
							
								48 2 4
							 | 
							latlem12 | 
							⊢ ( ( 𝐾  ∈  Lat  ∧  ( 𝐶  ∈  ( Base ‘ 𝐾 )  ∧  ( 𝑄  ∨  𝑇 )  ∈  ( Base ‘ 𝐾 )  ∧  ( 𝑅  ∨  𝑇 )  ∈  ( Base ‘ 𝐾 ) ) )  →  ( ( 𝐶  ≤  ( 𝑄  ∨  𝑇 )  ∧  𝐶  ≤  ( 𝑅  ∨  𝑇 ) )  ↔  𝐶  ≤  ( ( 𝑄  ∨  𝑇 )  ∧  ( 𝑅  ∨  𝑇 ) ) ) )  | 
						
						
							| 65 | 
							
								45 63 46 55 64
							 | 
							syl13anc | 
							⊢ ( 𝜑  →  ( ( 𝐶  ≤  ( 𝑄  ∨  𝑇 )  ∧  𝐶  ≤  ( 𝑅  ∨  𝑇 ) )  ↔  𝐶  ≤  ( ( 𝑄  ∨  𝑇 )  ∧  ( 𝑅  ∨  𝑇 ) ) ) )  | 
						
						
							| 66 | 
							
								65
							 | 
							adantr | 
							⊢ ( ( 𝜑  ∧  𝐶  =  𝐷 )  →  ( ( 𝐶  ≤  ( 𝑄  ∨  𝑇 )  ∧  𝐶  ≤  ( 𝑅  ∨  𝑇 ) )  ↔  𝐶  ≤  ( ( 𝑄  ∨  𝑇 )  ∧  ( 𝑅  ∨  𝑇 ) ) ) )  | 
						
						
							| 67 | 
							
								52 60 66
							 | 
							mpbi2and | 
							⊢ ( ( 𝜑  ∧  𝐶  =  𝐷 )  →  𝐶  ≤  ( ( 𝑄  ∨  𝑇 )  ∧  ( 𝑅  ∨  𝑇 ) ) )  | 
						
						
							| 68 | 
							
								
							 | 
							hlatl | 
							⊢ ( 𝐾  ∈  HL  →  𝐾  ∈  AtLat )  | 
						
						
							| 69 | 
							
								15 68
							 | 
							syl | 
							⊢ ( 𝜑  →  𝐾  ∈  AtLat )  | 
						
						
							| 70 | 
							
								43 17
							 | 
							eqeltrrd | 
							⊢ ( 𝜑  →  ( ( 𝑄  ∨  𝑇 )  ∧  ( 𝑅  ∨  𝑇 ) )  ∈  𝐴 )  | 
						
						
							| 71 | 
							
								2 5
							 | 
							atcmp | 
							⊢ ( ( 𝐾  ∈  AtLat  ∧  𝐶  ∈  𝐴  ∧  ( ( 𝑄  ∨  𝑇 )  ∧  ( 𝑅  ∨  𝑇 ) )  ∈  𝐴 )  →  ( 𝐶  ≤  ( ( 𝑄  ∨  𝑇 )  ∧  ( 𝑅  ∨  𝑇 ) )  ↔  𝐶  =  ( ( 𝑄  ∨  𝑇 )  ∧  ( 𝑅  ∨  𝑇 ) ) ) )  | 
						
						
							| 72 | 
							
								69 61 70 71
							 | 
							syl3anc | 
							⊢ ( 𝜑  →  ( 𝐶  ≤  ( ( 𝑄  ∨  𝑇 )  ∧  ( 𝑅  ∨  𝑇 ) )  ↔  𝐶  =  ( ( 𝑄  ∨  𝑇 )  ∧  ( 𝑅  ∨  𝑇 ) ) ) )  | 
						
						
							| 73 | 
							
								72
							 | 
							adantr | 
							⊢ ( ( 𝜑  ∧  𝐶  =  𝐷 )  →  ( 𝐶  ≤  ( ( 𝑄  ∨  𝑇 )  ∧  ( 𝑅  ∨  𝑇 ) )  ↔  𝐶  =  ( ( 𝑄  ∨  𝑇 )  ∧  ( 𝑅  ∨  𝑇 ) ) ) )  | 
						
						
							| 74 | 
							
								67 73
							 | 
							mpbid | 
							⊢ ( ( 𝜑  ∧  𝐶  =  𝐷 )  →  𝐶  =  ( ( 𝑄  ∨  𝑇 )  ∧  ( 𝑅  ∨  𝑇 ) ) )  | 
						
						
							| 75 | 
							
								44 74
							 | 
							eqtr4d | 
							⊢ ( ( 𝜑  ∧  𝐶  =  𝐷 )  →  𝑇  =  𝐶 )  | 
						
						
							| 76 | 
							
								75
							 | 
							ex | 
							⊢ ( 𝜑  →  ( 𝐶  =  𝐷  →  𝑇  =  𝐶 ) )  | 
						
						
							| 77 | 
							
								76
							 | 
							necon3d | 
							⊢ ( 𝜑  →  ( 𝑇  ≠  𝐶  →  𝐶  ≠  𝐷 ) )  | 
						
						
							| 78 | 
							
								14 77
							 | 
							mpd | 
							⊢ ( 𝜑  →  𝐶  ≠  𝐷 )  |