| Step | Hyp | Ref | Expression | 
						
							| 1 |  | nvmval.1 |  |-  X = ( BaseSet ` U ) | 
						
							| 2 |  | nvmval.2 |  |-  G = ( +v ` U ) | 
						
							| 3 |  | nvmval.4 |  |-  S = ( .sOLD ` U ) | 
						
							| 4 |  | nvmval.3 |  |-  M = ( -v ` U ) | 
						
							| 5 | 1 2 3 4 | nvmval |  |-  ( ( U e. NrmCVec /\ A e. X /\ B e. X ) -> ( A M B ) = ( A G ( -u 1 S B ) ) ) | 
						
							| 6 |  | neg1cn |  |-  -u 1 e. CC | 
						
							| 7 | 1 3 | nvscl |  |-  ( ( U e. NrmCVec /\ -u 1 e. CC /\ B e. X ) -> ( -u 1 S B ) e. X ) | 
						
							| 8 | 6 7 | mp3an2 |  |-  ( ( U e. NrmCVec /\ B e. X ) -> ( -u 1 S B ) e. X ) | 
						
							| 9 | 8 | 3adant2 |  |-  ( ( U e. NrmCVec /\ A e. X /\ B e. X ) -> ( -u 1 S B ) e. X ) | 
						
							| 10 | 1 2 | nvcom |  |-  ( ( U e. NrmCVec /\ A e. X /\ ( -u 1 S B ) e. X ) -> ( A G ( -u 1 S B ) ) = ( ( -u 1 S B ) G A ) ) | 
						
							| 11 | 9 10 | syld3an3 |  |-  ( ( U e. NrmCVec /\ A e. X /\ B e. X ) -> ( A G ( -u 1 S B ) ) = ( ( -u 1 S B ) G A ) ) | 
						
							| 12 | 5 11 | eqtrd |  |-  ( ( U e. NrmCVec /\ A e. X /\ B e. X ) -> ( A M B ) = ( ( -u 1 S B ) G A ) ) |