| Step | Hyp | Ref | Expression | 
						
							| 1 |  | nvrinv.1 |  |-  X = ( BaseSet ` U ) | 
						
							| 2 |  | nvrinv.2 |  |-  G = ( +v ` U ) | 
						
							| 3 |  | nvrinv.4 |  |-  S = ( .sOLD ` U ) | 
						
							| 4 |  | nvrinv.6 |  |-  Z = ( 0vec ` U ) | 
						
							| 5 | 2 | nvgrp |  |-  ( U e. NrmCVec -> G e. GrpOp ) | 
						
							| 6 | 1 2 | bafval |  |-  X = ran G | 
						
							| 7 |  | eqid |  |-  ( GId ` G ) = ( GId ` G ) | 
						
							| 8 |  | eqid |  |-  ( inv ` G ) = ( inv ` G ) | 
						
							| 9 | 6 7 8 | grpolinv |  |-  ( ( G e. GrpOp /\ A e. X ) -> ( ( ( inv ` G ) ` A ) G A ) = ( GId ` G ) ) | 
						
							| 10 | 5 9 | sylan |  |-  ( ( U e. NrmCVec /\ A e. X ) -> ( ( ( inv ` G ) ` A ) G A ) = ( GId ` G ) ) | 
						
							| 11 | 1 2 3 8 | nvinv |  |-  ( ( U e. NrmCVec /\ A e. X ) -> ( -u 1 S A ) = ( ( inv ` G ) ` A ) ) | 
						
							| 12 | 11 | oveq1d |  |-  ( ( U e. NrmCVec /\ A e. X ) -> ( ( -u 1 S A ) G A ) = ( ( ( inv ` G ) ` A ) G A ) ) | 
						
							| 13 | 2 4 | 0vfval |  |-  ( U e. NrmCVec -> Z = ( GId ` G ) ) | 
						
							| 14 | 13 | adantr |  |-  ( ( U e. NrmCVec /\ A e. X ) -> Z = ( GId ` G ) ) | 
						
							| 15 | 10 12 14 | 3eqtr4d |  |-  ( ( U e. NrmCVec /\ A e. X ) -> ( ( -u 1 S A ) G A ) = Z ) |