| Step | Hyp | Ref | Expression | 
						
							| 1 |  | 2atnelpln.j |  |-  .\/ = ( join ` K ) | 
						
							| 2 |  | 2atnelpln.a |  |-  A = ( Atoms ` K ) | 
						
							| 3 |  | 2atnelpln.p |  |-  P = ( LPlanes ` K ) | 
						
							| 4 |  | hllat |  |-  ( K e. HL -> K e. Lat ) | 
						
							| 5 | 4 | 3ad2ant1 |  |-  ( ( K e. HL /\ Q e. A /\ R e. A ) -> K e. Lat ) | 
						
							| 6 |  | eqid |  |-  ( Base ` K ) = ( Base ` K ) | 
						
							| 7 | 6 1 2 | hlatjcl |  |-  ( ( K e. HL /\ Q e. A /\ R e. A ) -> ( Q .\/ R ) e. ( Base ` K ) ) | 
						
							| 8 |  | eqid |  |-  ( le ` K ) = ( le ` K ) | 
						
							| 9 | 6 8 | latref |  |-  ( ( K e. Lat /\ ( Q .\/ R ) e. ( Base ` K ) ) -> ( Q .\/ R ) ( le ` K ) ( Q .\/ R ) ) | 
						
							| 10 | 5 7 9 | syl2anc |  |-  ( ( K e. HL /\ Q e. A /\ R e. A ) -> ( Q .\/ R ) ( le ` K ) ( Q .\/ R ) ) | 
						
							| 11 |  | simpl1 |  |-  ( ( ( K e. HL /\ Q e. A /\ R e. A ) /\ ( Q .\/ R ) e. P ) -> K e. HL ) | 
						
							| 12 |  | simpr |  |-  ( ( ( K e. HL /\ Q e. A /\ R e. A ) /\ ( Q .\/ R ) e. P ) -> ( Q .\/ R ) e. P ) | 
						
							| 13 |  | simpl2 |  |-  ( ( ( K e. HL /\ Q e. A /\ R e. A ) /\ ( Q .\/ R ) e. P ) -> Q e. A ) | 
						
							| 14 |  | simpl3 |  |-  ( ( ( K e. HL /\ Q e. A /\ R e. A ) /\ ( Q .\/ R ) e. P ) -> R e. A ) | 
						
							| 15 | 8 1 2 3 | lplnnle2at |  |-  ( ( K e. HL /\ ( ( Q .\/ R ) e. P /\ Q e. A /\ R e. A ) ) -> -. ( Q .\/ R ) ( le ` K ) ( Q .\/ R ) ) | 
						
							| 16 | 11 12 13 14 15 | syl13anc |  |-  ( ( ( K e. HL /\ Q e. A /\ R e. A ) /\ ( Q .\/ R ) e. P ) -> -. ( Q .\/ R ) ( le ` K ) ( Q .\/ R ) ) | 
						
							| 17 | 16 | ex |  |-  ( ( K e. HL /\ Q e. A /\ R e. A ) -> ( ( Q .\/ R ) e. P -> -. ( Q .\/ R ) ( le ` K ) ( Q .\/ R ) ) ) | 
						
							| 18 | 10 17 | mt2d |  |-  ( ( K e. HL /\ Q e. A /\ R e. A ) -> -. ( Q .\/ R ) e. P ) |