MHB Showing the Dual Basis is a basis

Click For Summary
The discussion centers on the dual space $V^*$ and its basis, which is dual to the basis of $V$, characterized by the relation $\alpha^i(e_j)=\delta_j^i$. The linear transformation $T: V \rightarrow \Bbb{R}$ can be expressed as $T(u)=<t,u>$ for some vector $t$, linking it to the dual basis forming a basis for $V^*$. This relationship is tied to the Riesz representation theorem, which provides a framework for understanding these concepts. Participants are encouraged to explore various resources for deeper insights into the theorem and its proof. The conversation highlights the importance of the Gram-Schmidt process in proving the equivalence of these statements.
joypav
Messages
149
Reaction score
0
I am working through a book with my professor and we read a section on the dual space, $V^*$.
It gives the basis dual to the basis of $V$ and proves that this is in fact a basis for $V^*$.
Characterized by $\alpha^i(e_j)=\delta_j^i$

I understand the proof given. But he said a different statement...
If $T: V \rightarrow \Bbb{R}$ is linear, then there is a vector $t$ so that $T(u)=<t,u>$. ($<\cdot, \cdot>$ is the inner product)

He said this is equivalent to showing that the dual basis forms a basis, and that it can be proven using the Gram-Schmidt process. I was wondering what that proof looks like? Even just an outline... I don't need all the details.
 
Physics news on Phys.org
Hi joypav,

The result your advisor mentioned is the Riesz representation theorem. There are many books, websites, and papers that you can look to for its statement and proof. Have a look at one and feel free to follow up with any questions.
 
Thread 'How to define a vector field?'
Hello! In one book I saw that function ##V## of 3 variables ##V_x, V_y, V_z## (vector field in 3D) can be decomposed in a Taylor series without higher-order terms (partial derivative of second power and higher) at point ##(0,0,0)## such way: I think so: higher-order terms can be neglected because partial derivative of second power and higher are equal to 0. Is this true? And how to define vector field correctly for this case? (In the book I found nothing and my attempt was wrong...

Similar threads

  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 23 ·
Replies
23
Views
2K
  • · Replies 52 ·
2
Replies
52
Views
4K
  • · Replies 1 ·
Replies
1
Views
2K
Replies
2
Views
1K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 15 ·
Replies
15
Views
2K