Subspaces

(1) What two properties must a non-empty subset of a vector space
have to be a vector subspace?

(2) In what geometrical objects are vector spaces of dimension 2?
What about of dimension 1?

(3) With each the span



is a vector subspace of . Verify this statement using the subspace theorem.
If , what is the maximum dimension of the subspace? (c.f. Span q.4)

(4) For a matrix, the solution space of is a subspace of .
True or false.

(5) If the rank of is , what is the dimension of the subspace of (4)?

(6) The rank is equal to the dimension of what subspaces related to ? (See Matrix equations q.6)