| Step | Hyp | Ref | Expression | 
						
							| 1 |  | cphipcj.h |  |-  ., = ( .i ` W ) | 
						
							| 2 |  | cphipcj.v |  |-  V = ( Base ` W ) | 
						
							| 3 |  | cphphl |  |-  ( W e. CPreHil -> W e. PreHil ) | 
						
							| 4 |  | eqid |  |-  ( Scalar ` W ) = ( Scalar ` W ) | 
						
							| 5 |  | eqid |  |-  ( 0g ` ( Scalar ` W ) ) = ( 0g ` ( Scalar ` W ) ) | 
						
							| 6 | 4 1 2 5 | iporthcom |  |-  ( ( W e. PreHil /\ A e. V /\ B e. V ) -> ( ( A ., B ) = ( 0g ` ( Scalar ` W ) ) <-> ( B ., A ) = ( 0g ` ( Scalar ` W ) ) ) ) | 
						
							| 7 | 3 6 | syl3an1 |  |-  ( ( W e. CPreHil /\ A e. V /\ B e. V ) -> ( ( A ., B ) = ( 0g ` ( Scalar ` W ) ) <-> ( B ., A ) = ( 0g ` ( Scalar ` W ) ) ) ) | 
						
							| 8 |  | cphclm |  |-  ( W e. CPreHil -> W e. CMod ) | 
						
							| 9 | 4 | clm0 |  |-  ( W e. CMod -> 0 = ( 0g ` ( Scalar ` W ) ) ) | 
						
							| 10 | 8 9 | syl |  |-  ( W e. CPreHil -> 0 = ( 0g ` ( Scalar ` W ) ) ) | 
						
							| 11 | 10 | 3ad2ant1 |  |-  ( ( W e. CPreHil /\ A e. V /\ B e. V ) -> 0 = ( 0g ` ( Scalar ` W ) ) ) | 
						
							| 12 | 11 | eqeq2d |  |-  ( ( W e. CPreHil /\ A e. V /\ B e. V ) -> ( ( A ., B ) = 0 <-> ( A ., B ) = ( 0g ` ( Scalar ` W ) ) ) ) | 
						
							| 13 | 11 | eqeq2d |  |-  ( ( W e. CPreHil /\ A e. V /\ B e. V ) -> ( ( B ., A ) = 0 <-> ( B ., A ) = ( 0g ` ( Scalar ` W ) ) ) ) | 
						
							| 14 | 7 12 13 | 3bitr4d |  |-  ( ( W e. CPreHil /\ A e. V /\ B e. V ) -> ( ( A ., B ) = 0 <-> ( B ., A ) = 0 ) ) |