| Step | Hyp | Ref | Expression | 
						
							| 1 |  | lbsss.v |  |-  V = ( Base ` W ) | 
						
							| 2 |  | lbsss.j |  |-  J = ( LBasis ` W ) | 
						
							| 3 |  | lbssp.n |  |-  N = ( LSpan ` W ) | 
						
							| 4 |  | elfvdm |  |-  ( B e. ( LBasis ` W ) -> W e. dom LBasis ) | 
						
							| 5 | 4 2 | eleq2s |  |-  ( B e. J -> W e. dom LBasis ) | 
						
							| 6 |  | eqid |  |-  ( Scalar ` W ) = ( Scalar ` W ) | 
						
							| 7 |  | eqid |  |-  ( .s ` W ) = ( .s ` W ) | 
						
							| 8 |  | eqid |  |-  ( Base ` ( Scalar ` W ) ) = ( Base ` ( Scalar ` W ) ) | 
						
							| 9 |  | eqid |  |-  ( 0g ` ( Scalar ` W ) ) = ( 0g ` ( Scalar ` W ) ) | 
						
							| 10 | 1 6 7 8 2 3 9 | islbs |  |-  ( W e. dom LBasis -> ( B e. J <-> ( B C_ V /\ ( N ` B ) = V /\ A. x e. B A. y e. ( ( Base ` ( Scalar ` W ) ) \ { ( 0g ` ( Scalar ` W ) ) } ) -. ( y ( .s ` W ) x ) e. ( N ` ( B \ { x } ) ) ) ) ) | 
						
							| 11 | 5 10 | syl |  |-  ( B e. J -> ( B e. J <-> ( B C_ V /\ ( N ` B ) = V /\ A. x e. B A. y e. ( ( Base ` ( Scalar ` W ) ) \ { ( 0g ` ( Scalar ` W ) ) } ) -. ( y ( .s ` W ) x ) e. ( N ` ( B \ { x } ) ) ) ) ) | 
						
							| 12 | 11 | ibi |  |-  ( B e. J -> ( B C_ V /\ ( N ` B ) = V /\ A. x e. B A. y e. ( ( Base ` ( Scalar ` W ) ) \ { ( 0g ` ( Scalar ` W ) ) } ) -. ( y ( .s ` W ) x ) e. ( N ` ( B \ { x } ) ) ) ) | 
						
							| 13 | 12 | simp2d |  |-  ( B e. J -> ( N ` B ) = V ) |