annihilator of vector subspace
If is a vector space, and is any subset of ,the annihilator
of , denoted by ,is the subspace
of the dual space
that kills every vector in :
Similarly, if is any subset of , the annihilated subspaceof is
(Note: this may not be the standard notation.)
1 Properties
Assume is finite-dimensional.Let and denote subspaces of and , respectively,and let denote the natural isomorphism from to its double dual .
- i.
- ii.
- iii.
- iv.
- v.
- vi.
(a dimension theorem)
- vii.
- viii.
, where denotesthe sum of two subspaces of .
- ix.
If is a linear operator, and ,then the image of the pullback is .
References
- 1 Friedberg, Insel, Spence. Linear Algebra. Prentice-Hall, 1997.