Is u + v in U if u and v are elements of V but not in U?

  • Context: Undergrad 
  • Thread starter Thread starter zenn
  • Start date Start date
  • Tags Tags
    Subspace
Click For Summary
SUMMARY

In the context of vector spaces, if U is a subspace of vector space V, and u and v are elements of V but not necessarily in U, the sum u + v can be in U under specific conditions. Notably, if u is not in U and v is defined as -u, then u + v equals 0, which is always in U. Conversely, if u + v is in U and u is in U, then v must also be in U, reinforcing the closure property of subspaces.

PREREQUISITES
  • Understanding of vector spaces and subspaces
  • Familiarity with vector addition and scalar multiplication
  • Knowledge of closure properties in linear algebra
  • Basic proof techniques in mathematics
NEXT STEPS
  • Study the properties of vector spaces and subspaces in linear algebra
  • Learn about closure properties and their implications in vector spaces
  • Explore proof techniques specific to linear algebra concepts
  • Investigate examples of subspaces in various vector spaces
USEFUL FOR

Students and educators in mathematics, particularly those focusing on linear algebra, as well as anyone interested in understanding the properties of vector spaces and subspaces.

zenn
Messages
2
Reaction score
0
Not sure how to prove the following:

If U is a subspace of a vector space V, and if u and v are elements of V, but one or both not in U, can u + v be in U?

Any help would be appreciated.
 
Physics news on Phys.org
v=-u

so, if u is not in U, then v=-u is not in U. But, u+v=0 is in U. The other case is false --- i.e., if u+v is in U and u is in U, then v has to be in U also. You should prove that yourself though.
 

Similar threads

  • · Replies 10 ·
Replies
10
Views
3K
  • · Replies 12 ·
Replies
12
Views
3K
  • · Replies 9 ·
Replies
9
Views
2K
Replies
2
Views
2K
  • · Replies 4 ·
Replies
4
Views
1K
  • · Replies 9 ·
Replies
9
Views
2K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 19 ·
Replies
19
Views
6K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 13 ·
Replies
13
Views
5K