Theorems from Subspaces
All theorems from Subspaces.
Subspace test
Let be a subset of a vector space over , with the operations inherited from . Then is a subspace of if and only if:
- is non-empty;
- is closed under vector addition: implies ;
- is closed under scalar multiplication: and imply .
Non-emptiness and scalar closure supply the zero vector and additive inverses, so these three conditions are enough.