| Step | Hyp | Ref | Expression | 
						
							| 1 |  | cphipcj.h |  |-  ., = ( .i ` W ) | 
						
							| 2 |  | cphipcj.v |  |-  V = ( Base ` W ) | 
						
							| 3 |  | cphsubdir.m |  |-  .- = ( -g ` W ) | 
						
							| 4 |  | cph2subdi.1 |  |-  ( ph -> W e. CPreHil ) | 
						
							| 5 |  | cph2subdi.2 |  |-  ( ph -> A e. V ) | 
						
							| 6 |  | cph2subdi.3 |  |-  ( ph -> B e. V ) | 
						
							| 7 |  | cph2subdi.4 |  |-  ( ph -> C e. V ) | 
						
							| 8 |  | cph2subdi.5 |  |-  ( ph -> D e. V ) | 
						
							| 9 |  | cphclm |  |-  ( W e. CPreHil -> W e. CMod ) | 
						
							| 10 | 4 9 | syl |  |-  ( ph -> W e. CMod ) | 
						
							| 11 |  | eqid |  |-  ( Scalar ` W ) = ( Scalar ` W ) | 
						
							| 12 | 11 | clmadd |  |-  ( W e. CMod -> + = ( +g ` ( Scalar ` W ) ) ) | 
						
							| 13 | 10 12 | syl |  |-  ( ph -> + = ( +g ` ( Scalar ` W ) ) ) | 
						
							| 14 | 13 | oveqd |  |-  ( ph -> ( ( A ., C ) + ( B ., D ) ) = ( ( A ., C ) ( +g ` ( Scalar ` W ) ) ( B ., D ) ) ) | 
						
							| 15 | 13 | oveqd |  |-  ( ph -> ( ( A ., D ) + ( B ., C ) ) = ( ( A ., D ) ( +g ` ( Scalar ` W ) ) ( B ., C ) ) ) | 
						
							| 16 | 14 15 | oveq12d |  |-  ( ph -> ( ( ( A ., C ) + ( B ., D ) ) ( -g ` ( Scalar ` W ) ) ( ( A ., D ) + ( B ., C ) ) ) = ( ( ( A ., C ) ( +g ` ( Scalar ` W ) ) ( B ., D ) ) ( -g ` ( Scalar ` W ) ) ( ( A ., D ) ( +g ` ( Scalar ` W ) ) ( B ., C ) ) ) ) | 
						
							| 17 |  | cphphl |  |-  ( W e. CPreHil -> W e. PreHil ) | 
						
							| 18 | 4 17 | syl |  |-  ( ph -> W e. PreHil ) | 
						
							| 19 |  | eqid |  |-  ( Base ` ( Scalar ` W ) ) = ( Base ` ( Scalar ` W ) ) | 
						
							| 20 | 11 1 2 19 | ipcl |  |-  ( ( W e. PreHil /\ A e. V /\ C e. V ) -> ( A ., C ) e. ( Base ` ( Scalar ` W ) ) ) | 
						
							| 21 | 18 5 7 20 | syl3anc |  |-  ( ph -> ( A ., C ) e. ( Base ` ( Scalar ` W ) ) ) | 
						
							| 22 | 11 1 2 19 | ipcl |  |-  ( ( W e. PreHil /\ B e. V /\ D e. V ) -> ( B ., D ) e. ( Base ` ( Scalar ` W ) ) ) | 
						
							| 23 | 18 6 8 22 | syl3anc |  |-  ( ph -> ( B ., D ) e. ( Base ` ( Scalar ` W ) ) ) | 
						
							| 24 | 11 19 | clmacl |  |-  ( ( W e. CMod /\ ( A ., C ) e. ( Base ` ( Scalar ` W ) ) /\ ( B ., D ) e. ( Base ` ( Scalar ` W ) ) ) -> ( ( A ., C ) + ( B ., D ) ) e. ( Base ` ( Scalar ` W ) ) ) | 
						
							| 25 | 10 21 23 24 | syl3anc |  |-  ( ph -> ( ( A ., C ) + ( B ., D ) ) e. ( Base ` ( Scalar ` W ) ) ) | 
						
							| 26 | 11 1 2 19 | ipcl |  |-  ( ( W e. PreHil /\ A e. V /\ D e. V ) -> ( A ., D ) e. ( Base ` ( Scalar ` W ) ) ) | 
						
							| 27 | 18 5 8 26 | syl3anc |  |-  ( ph -> ( A ., D ) e. ( Base ` ( Scalar ` W ) ) ) | 
						
							| 28 | 11 1 2 19 | ipcl |  |-  ( ( W e. PreHil /\ B e. V /\ C e. V ) -> ( B ., C ) e. ( Base ` ( Scalar ` W ) ) ) | 
						
							| 29 | 18 6 7 28 | syl3anc |  |-  ( ph -> ( B ., C ) e. ( Base ` ( Scalar ` W ) ) ) | 
						
							| 30 | 11 19 | clmacl |  |-  ( ( W e. CMod /\ ( A ., D ) e. ( Base ` ( Scalar ` W ) ) /\ ( B ., C ) e. ( Base ` ( Scalar ` W ) ) ) -> ( ( A ., D ) + ( B ., C ) ) e. ( Base ` ( Scalar ` W ) ) ) | 
						
							| 31 | 10 27 29 30 | syl3anc |  |-  ( ph -> ( ( A ., D ) + ( B ., C ) ) e. ( Base ` ( Scalar ` W ) ) ) | 
						
							| 32 | 11 19 | clmsub |  |-  ( ( W e. CMod /\ ( ( A ., C ) + ( B ., D ) ) e. ( Base ` ( Scalar ` W ) ) /\ ( ( A ., D ) + ( B ., C ) ) e. ( Base ` ( Scalar ` W ) ) ) -> ( ( ( A ., C ) + ( B ., D ) ) - ( ( A ., D ) + ( B ., C ) ) ) = ( ( ( A ., C ) + ( B ., D ) ) ( -g ` ( Scalar ` W ) ) ( ( A ., D ) + ( B ., C ) ) ) ) | 
						
							| 33 | 10 25 31 32 | syl3anc |  |-  ( ph -> ( ( ( A ., C ) + ( B ., D ) ) - ( ( A ., D ) + ( B ., C ) ) ) = ( ( ( A ., C ) + ( B ., D ) ) ( -g ` ( Scalar ` W ) ) ( ( A ., D ) + ( B ., C ) ) ) ) | 
						
							| 34 |  | eqid |  |-  ( -g ` ( Scalar ` W ) ) = ( -g ` ( Scalar ` W ) ) | 
						
							| 35 |  | eqid |  |-  ( +g ` ( Scalar ` W ) ) = ( +g ` ( Scalar ` W ) ) | 
						
							| 36 | 11 1 2 3 34 35 18 5 6 7 8 | ip2subdi |  |-  ( ph -> ( ( A .- B ) ., ( C .- D ) ) = ( ( ( A ., C ) ( +g ` ( Scalar ` W ) ) ( B ., D ) ) ( -g ` ( Scalar ` W ) ) ( ( A ., D ) ( +g ` ( Scalar ` W ) ) ( B ., C ) ) ) ) | 
						
							| 37 | 16 33 36 | 3eqtr4rd |  |-  ( ph -> ( ( A .- B ) ., ( C .- D ) ) = ( ( ( A ., C ) + ( B ., D ) ) - ( ( A ., D ) + ( B ., C ) ) ) ) |