Proving Vector Space Subspace Union: Tips and Assistance"

Click For Summary

Discussion Overview

The discussion revolves around a problem related to vector spaces, specifically proving a property of the union of two subspaces. The participants explore the conditions under which the union of two subspaces is itself a subspace.

Discussion Character

  • Homework-related, Mathematical reasoning, Debate/contested

Main Points Raised

  • One participant presents a problem regarding the union of two subspaces W1 and W2 of a vector space V, asking for assistance in proving that if their union is a subspace, then one must be contained within the other.
  • Another participant suggests proving the contrapositive, indicating that if neither W1 is contained in W2 nor W2 in W1, then their union cannot be a subspace, hinting at closure under addition as a key point.
  • A subsequent post mentions using contradiction as a method to approach the proof.
  • One participant reports success in completing the proof using the contradiction method.
  • A separate participant inquires about discussions related to applied mathematics, indicating a shift in topic from the original problem.
  • Another participant questions the meaning of "applied maths," suggesting a lack of clarity on the term within the context of the discussion.

Areas of Agreement / Disagreement

There is no consensus on the original problem's proof method, as participants present different approaches. Additionally, the discussion about applied mathematics introduces a new topic that is not directly related to the initial problem.

Contextual Notes

The discussion includes assumptions about the properties of vector spaces and subspaces, but these are not explicitly stated. The transition to applied mathematics raises questions about definitions that remain unresolved.

Who May Find This Useful

Students and individuals interested in vector space theory, mathematical proofs, and those seeking discussions on applied mathematics may find this thread relevant.

ambuj123
Messages
65
Reaction score
0
Hello

Well i hv just started vector spaces and well am finding difficulty in proving this hoffman and kunze problem could some 1 help me :(

Question : W1 and W2 be sub-spaces of vector space V such that set-theoritic union of W1 and W2 is also a Subspace . Proove that one of the subspace Wi is contained in other ?

Thank You
 
Physics news on Phys.org
so you have that W_1, W_2 are subspaces

you need to show that if W_1 U W_2 is a subspace then W_1 is contained in W_2, or W_2 is contained in W_1

the contrapositive is easier to prove, you should show that
if W_1 is not contained in W_2 and W_2 is not contained in W_1, then W_1 U W_2 is not a subspace
hint: W_1 U W_2 won't be closed under addition, show this and you are done
 
i.e. use contradiction.
 
Hey thanks was able to do the proof by proving the contradicton
 
Where is Applied maths

Please I want to know if there is a forum that is talking about applied maths ..

If there. u can send me an e-mail at>>> ( ahmedtomyus@yahoo.com )
 
What do you mean by "applied maths"?
 

Similar threads

  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 8 ·
Replies
8
Views
3K
  • · Replies 7 ·
Replies
7
Views
3K
  • · Replies 1 ·
Replies
1
Views
3K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 7 ·
Replies
7
Views
3K
  • · Replies 4 ·
Replies
4
Views
3K
  • · Replies 1 ·
Replies
1
Views
3K
  • · Replies 5 ·
Replies
5
Views
2K