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1 answer
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Conditions of P for existence of orthogonal matrix Q and permutation matrix U satisfying QP = PU

Question: Let $P\in \mathbb{R}^{d\times n}$ be a $d$-rank real matrix and $PP^T = c I_d$ with a certain constant $c > 0$. Under what additional conditions of $P$ does there exist an orthogonal ...
Eddie's user avatar
  • 187
15 votes
2 answers
480 views

matrix inequality with orthogonal matrices

I would like to know if for $A,B\in SO(3)$ the inequality $$ \|AB-BA\|_F\leq \|A-I\|_F\|B-I\|_F $$ holds, where $\|\cdot\|_F$ denotes the Frobenius norm and $I$ the identity matrix. Using the identity ...
Markus Sprecher's user avatar
5 votes
2 answers
495 views

Existence of parametrizations of rational orthogonal matrices

I suppose that there are formulas which parametrize all the orthogonal matrices with rational coefficients. Does anyone know anything about it? And what are some publications that discuss this? Thanks....
jose luis leal's user avatar