Skip to main content
In cases like this, \left and \right influence horizontal spacing.
Source Link
Michael Hardy
  • 1
  • 12
  • 85
  • 126

Is it true $\|\log$\left\|\log(RS)\|≤\|\log\right\|≤\left\|\log(R)+\log(S)\|$\right\|$ for all $R,S \in \mathrm{SO}(3)$, where $\|\cdot\|$ is the Frobenius norm?

$\DeclareMathOperator\SO{SO}$I asked this initially in math stack exchange, but thought to ask it here since it is more advanced and related to my research topic. I study optimization on Lie groups from a Riemannian geometry viewpoint. Naturally, one of the Lie groups I use the most is $\SO(3) \subset \mathbb{R}^{3 \times 3}$ equipped with the bi-invariant metric $\langle \xi, \eta\rangle = \frac{1}{2} \operatorname{tr}(\xi^T\eta )$, where $\xi,\eta \in \mathfrak{so}(3)$ are $3 \times 3$ skew-symmetric matrices. The way I parameterize $\SO(3)$ and $\mathfrak{so}(3)$ is not important ofc. I could just as easily use unit quaternions.

Lately in my studies, I've been interested in commutation error, and ways to bound it.

I was especially curious if there existed $K > 0$ such that $$\|\log(R^{-1}S)\| \leq K \|\log(S) - \log(R)\|$$$$\left\|\log(R^{-1}S)\right\| \leq K \left\|\log(S) - \log(R)\right\|$$ for all $R,S \in \SO(3)$ such that $\log(S), \log(R), \log(R^{-1}S)$ exists. Here, $\log(\cdot)$ is the Lie logarithm. Under my parameterization, it coincides with the matrix logarithm.

After generating random rotation matrices $R,S$ in a script, to my surprise I found $K=1$ every single time. I have yet to randomly generate or analytically derive a counterexample. Once again, I am only focusing on pairs $(R,S)$ such that each term above exists.

If true, this is a very powerful inequality! I'm surprised to see very little discussion about online. Surely, someone must've noticed this. Any idea how I could prove this?

Is it true $\|\log(RS)\|≤\|\log(R)+\log(S)\|$ for all $R,S \in \mathrm{SO}(3)$, where $\|\cdot\|$ is the Frobenius norm?

$\DeclareMathOperator\SO{SO}$I asked this initially in math stack exchange, but thought to ask it here since it is more advanced and related to my research topic. I study optimization on Lie groups from a Riemannian geometry viewpoint. Naturally, one of the Lie groups I use the most is $\SO(3) \subset \mathbb{R}^{3 \times 3}$ equipped with the bi-invariant metric $\langle \xi, \eta\rangle = \frac{1}{2} \operatorname{tr}(\xi^T\eta )$, where $\xi,\eta \in \mathfrak{so}(3)$ are $3 \times 3$ skew-symmetric matrices. The way I parameterize $\SO(3)$ and $\mathfrak{so}(3)$ is not important ofc. I could just as easily use unit quaternions.

Lately in my studies, I've been interested in commutation error, and ways to bound it.

I was especially curious if there existed $K > 0$ such that $$\|\log(R^{-1}S)\| \leq K \|\log(S) - \log(R)\|$$ for all $R,S \in \SO(3)$ such that $\log(S), \log(R), \log(R^{-1}S)$ exists. Here, $\log(\cdot)$ is the Lie logarithm. Under my parameterization, it coincides with the matrix logarithm.

After generating random rotation matrices $R,S$ in a script, to my surprise I found $K=1$ every single time. I have yet to randomly generate or analytically derive a counterexample. Once again, I am only focusing on pairs $(R,S)$ such that each term above exists.

If true, this is a very powerful inequality! I'm surprised to see very little discussion about online. Surely, someone must've noticed this. Any idea how I could prove this?

Is it true $\left\|\log(RS)\right\|≤\left\|\log(R)+\log(S)\right\|$ for all $R,S \in \mathrm{SO}(3)$, where $\|\cdot\|$ is the Frobenius norm?

$\DeclareMathOperator\SO{SO}$I asked this initially in math stack exchange, but thought to ask it here since it is more advanced and related to my research topic. I study optimization on Lie groups from a Riemannian geometry viewpoint. Naturally, one of the Lie groups I use the most is $\SO(3) \subset \mathbb{R}^{3 \times 3}$ equipped with the bi-invariant metric $\langle \xi, \eta\rangle = \frac{1}{2} \operatorname{tr}(\xi^T\eta )$, where $\xi,\eta \in \mathfrak{so}(3)$ are $3 \times 3$ skew-symmetric matrices. The way I parameterize $\SO(3)$ and $\mathfrak{so}(3)$ is not important ofc. I could just as easily use unit quaternions.

Lately in my studies, I've been interested in commutation error, and ways to bound it.

I was especially curious if there existed $K > 0$ such that $$\left\|\log(R^{-1}S)\right\| \leq K \left\|\log(S) - \log(R)\right\|$$ for all $R,S \in \SO(3)$ such that $\log(S), \log(R), \log(R^{-1}S)$ exists. Here, $\log(\cdot)$ is the Lie logarithm. Under my parameterization, it coincides with the matrix logarithm.

After generating random rotation matrices $R,S$ in a script, to my surprise I found $K=1$ every single time. I have yet to randomly generate or analytically derive a counterexample. Once again, I am only focusing on pairs $(R,S)$ such that each term above exists.

If true, this is a very powerful inequality! I'm surprised to see very little discussion about online. Surely, someone must've noticed this. Any idea how I could prove this?

formatting
Source Link
YCor
  • 63.9k
  • 5
  • 187
  • 286

Is it true $\|\log(RS)\|≤\|\log(R)+\log(S)\|$ for all $R,S \in SO\mathrm{SO}(3)$, where $\|\cdot\|$ is the Frobenius norm?

I$\DeclareMathOperator\SO{SO}$I asked this initially in math stack exchange, but thought to ask it here since it is more advanced and related to my research topic. I study optimization on Lie groups from a Riemannian geometry viewpoint. Naturally, one of the Lie groups I use the most is $SO(3) \subset \mathbb{R}^{3 \times 3}$$\SO(3) \subset \mathbb{R}^{3 \times 3}$ equipped with the bi-invariant metric $\langle \xi, \eta\rangle = \frac{1}{2} \operatorname{tr}(\xi^T\eta )$, where $\xi,\eta \in \mathfrak{so}(3)$ are $3 \times 3$ skew-symmetric matrices. The way I parameterize $SO(3)$$\SO(3)$ and $\mathfrak{so}(3)$ is not important ofc. I could just as easily use unit quaternions.

Lately in my studies, I've been interested in commutation error, and ways to bound it.

I was especially curious if there existed $K > 0$ such that $$\|\log(R^{-1}S)\| \leq K \|\log(S) - \log(R)\|$$ for all $R,S \in SO(3)$$R,S \in \SO(3)$ such that $\log(S), \log(R), \log(R^{-1}S)$ exists. Here, $\log(\cdot)$ is the Lie logarithm. Under my parameterization, it coincides with the matrix logarithm.

After generating random rotation matrices $R,S$ in a script, to my suprisesurprise I found $K=1$ every single time. I have yet to randomly generate or analytically derive a counterexample. Once again, I am only focusing on pairs $(R,S)$ such that each term above exists.

If true, this is a very powerful inequality! I'm surprised to see very little discussion about online. Surely, someone must've noticed this. Any idea how I could prove this?

Is it true $\|\log(RS)\|≤\|\log(R)+\log(S)\|$ for all $R,S \in SO(3)$, where $\|\cdot\|$ is the Frobenius norm?

I asked this initially in math stack exchange, but thought to ask it here since it is more advanced and related to my research topic. I study optimization on Lie groups from a Riemannian geometry viewpoint. Naturally, one of the Lie groups I use the most is $SO(3) \subset \mathbb{R}^{3 \times 3}$ equipped with the bi-invariant metric $\langle \xi, \eta\rangle = \frac{1}{2} \operatorname{tr}(\xi^T\eta )$, where $\xi,\eta \in \mathfrak{so}(3)$ are $3 \times 3$ skew-symmetric matrices. The way I parameterize $SO(3)$ and $\mathfrak{so}(3)$ is not important ofc. I could just as easily use unit quaternions.

Lately in my studies, I've been interested in commutation error, and ways to bound it.

I was especially curious if there existed $K > 0$ such that $$\|\log(R^{-1}S)\| \leq K \|\log(S) - \log(R)\|$$ for all $R,S \in SO(3)$ such that $\log(S), \log(R), \log(R^{-1}S)$ exists. Here, $\log(\cdot)$ is the Lie logarithm. Under my parameterization, it coincides with the matrix logarithm.

After generating random rotation matrices $R,S$ in a script, to my suprise I found $K=1$ every single time. I have yet to randomly generate or analytically derive a counterexample. Once again, I am only focusing on pairs $(R,S)$ such that each term above exists.

If true, this is a very powerful inequality! I'm surprised to see very little discussion about online. Surely, someone must've noticed this. Any idea how I could prove this?

Is it true $\|\log(RS)\|≤\|\log(R)+\log(S)\|$ for all $R,S \in \mathrm{SO}(3)$, where $\|\cdot\|$ is the Frobenius norm?

$\DeclareMathOperator\SO{SO}$I asked this initially in math stack exchange, but thought to ask it here since it is more advanced and related to my research topic. I study optimization on Lie groups from a Riemannian geometry viewpoint. Naturally, one of the Lie groups I use the most is $\SO(3) \subset \mathbb{R}^{3 \times 3}$ equipped with the bi-invariant metric $\langle \xi, \eta\rangle = \frac{1}{2} \operatorname{tr}(\xi^T\eta )$, where $\xi,\eta \in \mathfrak{so}(3)$ are $3 \times 3$ skew-symmetric matrices. The way I parameterize $\SO(3)$ and $\mathfrak{so}(3)$ is not important ofc. I could just as easily use unit quaternions.

Lately in my studies, I've been interested in commutation error, and ways to bound it.

I was especially curious if there existed $K > 0$ such that $$\|\log(R^{-1}S)\| \leq K \|\log(S) - \log(R)\|$$ for all $R,S \in \SO(3)$ such that $\log(S), \log(R), \log(R^{-1}S)$ exists. Here, $\log(\cdot)$ is the Lie logarithm. Under my parameterization, it coincides with the matrix logarithm.

After generating random rotation matrices $R,S$ in a script, to my surprise I found $K=1$ every single time. I have yet to randomly generate or analytically derive a counterexample. Once again, I am only focusing on pairs $(R,S)$ such that each term above exists.

If true, this is a very powerful inequality! I'm surprised to see very little discussion about online. Surely, someone must've noticed this. Any idea how I could prove this?

added 19 characters in body; edited title
Source Link
Michael Hardy
  • 1
  • 12
  • 85
  • 126

Is it true $‖\log$\|\log(RS)‖≤\|\log\|≤\|\log(R)+\log(S)\|$ for all $R,S \in SO(3)$, where $\|.\|$$\|\cdot\|$ is the Frobenius norm?

I asked this initially in math stack exchange, but thought to ask it here since it is more advanced and related to my research topic. I study optimization on Lie groups from a Riemannian geometry viewpoint. Naturally, one of the Lie groups I use the most is $SO(3) \subset \mathbb{R}^{3 \times 3}$ equipped with the bi-invariant metric $\langle \xi, \eta\rangle = \frac{1}{2} tr(\xi^T\eta )$$\langle \xi, \eta\rangle = \frac{1}{2} \operatorname{tr}(\xi^T\eta )$, where $\xi,\eta \in \mathfrak{so}(3)$ are $3 \times 3$ skew-symmetric matrices. The way I parameterize $SO(3)$ and $\mathfrak{so}(3)$ is not important ofc. I could just as easily use unit quaternions.

Lately in my studies, I've been interested in commutation error, and ways to bound it.

I was especially curious if there existed $K > 0$ such that $$\|\log(R^{-1}S)\| \leq K \|\log(S) - \log(R)\|$$ for all $R,S \in SO(3)$ such that $\log(S), \log(R), \log(R^{-1}S)$ exists. Here, $\log(.)$$\log(\cdot)$ is the Lie logarithm. Under my parameterization, it coincides with the matrix logarithm.

After generating random rotation matrices $R,S$ in a script, to my suprise I found $K=1$ every single time. I have yet to randomly generate or analytically derive a counterexample. Once again, I am only focusing on pairs $(R,S)$ such that each term above exists.

If true, this is a very powerful inequality! I'm surprised to see very little discussion about online. Surely, someone must've noticed this. Any idea how I could prove this?

Is it true $‖\log(RS)‖≤\|\log(R)+\log(S)\|$ for all $R,S \in SO(3)$, where $\|.\|$ is the Frobenius norm?

I asked this initially in math stack exchange, but thought to ask it here since it is more advanced and related to my research topic. I study optimization on Lie groups from a Riemannian geometry viewpoint. Naturally, one of the Lie groups I use the most is $SO(3) \subset \mathbb{R}^{3 \times 3}$ equipped with the bi-invariant metric $\langle \xi, \eta\rangle = \frac{1}{2} tr(\xi^T\eta )$, where $\xi,\eta \in \mathfrak{so}(3)$ are $3 \times 3$ skew-symmetric matrices. The way I parameterize $SO(3)$ and $\mathfrak{so}(3)$ is not important ofc. I could just as easily use unit quaternions.

Lately in my studies, I've been interested in commutation error, and ways to bound it.

I was especially curious if there existed $K > 0$ such that $$\|\log(R^{-1}S)\| \leq K \|\log(S) - \log(R)\|$$ for all $R,S \in SO(3)$ such that $\log(S), \log(R), \log(R^{-1}S)$ exists. Here, $\log(.)$ is the Lie logarithm. Under my parameterization, it coincides with the matrix logarithm.

After generating random rotation matrices $R,S$ in a script, to my suprise I found $K=1$ every single time. I have yet to randomly generate or analytically derive a counterexample. Once again, I am only focusing on pairs $(R,S)$ such that each term above exists.

If true, this is a very powerful inequality! I'm surprised to see very little discussion about online. Surely, someone must've noticed this. Any idea how I could prove this?

Is it true $\|\log(RS)\|≤\|\log(R)+\log(S)\|$ for all $R,S \in SO(3)$, where $\|\cdot\|$ is the Frobenius norm?

I asked this initially in math stack exchange, but thought to ask it here since it is more advanced and related to my research topic. I study optimization on Lie groups from a Riemannian geometry viewpoint. Naturally, one of the Lie groups I use the most is $SO(3) \subset \mathbb{R}^{3 \times 3}$ equipped with the bi-invariant metric $\langle \xi, \eta\rangle = \frac{1}{2} \operatorname{tr}(\xi^T\eta )$, where $\xi,\eta \in \mathfrak{so}(3)$ are $3 \times 3$ skew-symmetric matrices. The way I parameterize $SO(3)$ and $\mathfrak{so}(3)$ is not important ofc. I could just as easily use unit quaternions.

Lately in my studies, I've been interested in commutation error, and ways to bound it.

I was especially curious if there existed $K > 0$ such that $$\|\log(R^{-1}S)\| \leq K \|\log(S) - \log(R)\|$$ for all $R,S \in SO(3)$ such that $\log(S), \log(R), \log(R^{-1}S)$ exists. Here, $\log(\cdot)$ is the Lie logarithm. Under my parameterization, it coincides with the matrix logarithm.

After generating random rotation matrices $R,S$ in a script, to my suprise I found $K=1$ every single time. I have yet to randomly generate or analytically derive a counterexample. Once again, I am only focusing on pairs $(R,S)$ such that each term above exists.

If true, this is a very powerful inequality! I'm surprised to see very little discussion about online. Surely, someone must've noticed this. Any idea how I could prove this?

Source Link
Loading