Proving the Direct Sum Decomposition of a Vector Space

In summary, the conversation discusses the proof that for a basis B = {u1, u2.. un} of a vector space V, U = {u1, u2...ui} and W = {ui+1, ui+2... un} are subspaces that span V and have a nontrivial intersection. The goal is to prove that V can be decomposed into the direct sum of U and W. The approach involves showing that the elements in U and W are not in each other, and that a nonzero vector v in their intersection must be dependent.
  • #1
ashina14
34
0

Homework Statement



Suppose B = {u1, u2.. un} is a basis of V. Let U = {u1, u2...ui} and W = {ui+1, ui+2... un}. Prove that V = U ⊕ W.

Homework Equations





The Attempt at a Solution



I think I should prove that elements in U are not in W and viceversa. Then this prove it is indeed a disjunction?
 
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  • #2
Prove that if v is a nonzero vector in the intersection of U and W, then the u'is must be dependent.
 
  • #3
How can I show v is non zero?
 
  • #4
ashina14 said:
How can I show v is non zero?
You assume that v is nonzero - that's what "if v is nonzero" means. You don't need to show the things that you are assuming.
 
  • #5
Thanks for the help guys :)
 

FAQ: Proving the Direct Sum Decomposition of a Vector Space

What is a vector space?

A vector space is a mathematical structure consisting of a set of objects called vectors, which can be added together and multiplied by numbers, called scalars, to produce new vectors. It is a fundamental concept in linear algebra and is used to study geometric properties and transformations.

What are the properties of a vector space?

A vector space must satisfy several properties, including closure under vector addition and scalar multiplication, associativity and commutativity of addition, and the existence of a zero vector and additive inverses for each vector. It must also follow the distributive property of scalar multiplication over vector addition.

How is a vector space different from a Euclidean space?

A vector space is a more general concept than a Euclidean space. While a Euclidean space is a vector space, not all vector spaces are Euclidean spaces. A Euclidean space has additional structure, such as a defined distance and angle between vectors, while a vector space only has the operations of vector addition and scalar multiplication.

What are some examples of vector spaces?

Some common examples of vector spaces include the set of all real numbers, the set of all n-dimensional vectors, and the set of all polynomials with real coefficients. Other examples include the set of all continuous functions on a given interval and the set of all square matrices of a given size.

What is the dimension of a vector space?

The dimension of a vector space is the number of vectors in a basis for that space. A basis is a set of linearly independent vectors that span the entire space. The dimension of a vector space can also be thought of as the number of coordinates needed to specify any vector in that space.

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