- #1
Constantinos
- 83
- 1
Hey! So here's the question:
Let
[itex]\mathbf{B} \in \mathbb{R}^{n \times n}[/itex] be some square matrix we can choose and
[itex]\mathbf{D} \in \mathbb{R}^{n \times n}[/itex] be some given diagonal matrix with positive diagonal elements.
For what matrices [itex]\mathbf{B}[/itex] is the product
[itex]\mathbf{BDB}^{T}[/itex]
a diagonal matrix?
Anything goes here I guess. It could be something very easy or requiring theorems (SVD ?)
Well I tried to do this for [itex] \mathbf{B}, \mathbf{D} \in \mathbb{R}^{2 \times 2}[/itex] and the matrix that satisfies the above could be diagonal, anti-diagonal, or even have a row zeroed (but not column). So it can't be something simple, like just saying that it should be diagonal (which is rather obvious)
If anyone has anything to suggest feel free, thanks!
Homework Statement
Let
[itex]\mathbf{B} \in \mathbb{R}^{n \times n}[/itex] be some square matrix we can choose and
[itex]\mathbf{D} \in \mathbb{R}^{n \times n}[/itex] be some given diagonal matrix with positive diagonal elements.
For what matrices [itex]\mathbf{B}[/itex] is the product
[itex]\mathbf{BDB}^{T}[/itex]
a diagonal matrix?
Homework Equations
Anything goes here I guess. It could be something very easy or requiring theorems (SVD ?)
The Attempt at a Solution
Well I tried to do this for [itex] \mathbf{B}, \mathbf{D} \in \mathbb{R}^{2 \times 2}[/itex] and the matrix that satisfies the above could be diagonal, anti-diagonal, or even have a row zeroed (but not column). So it can't be something simple, like just saying that it should be diagonal (which is rather obvious)
If anyone has anything to suggest feel free, thanks!
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