A very short note on a problem of Godsil and Sun
Wei Wang
Abstract
Using the spectral theorem for symmetric matrices over a real closed field, we give a quick answer to a problem of Godsil and Sun on degree-similarity of graphs.
Wei Wang
Using the spectral theorem for symmetric matrices over a real closed field, we give a quick answer to a problem of Godsil and Sun on degree-similarity of graphs.
This paper contains 1 section, 1 theorem, 2 equations.
Theorem 1
Let $K$ and $L$ be two symmetric matrices over $\mathbb{Q}(\mu)$. Then the following two assertions are equivalent: (i)$\det(tI-K)=\det(tI-L)$; (ii)$K$ and $L$ are similar over $\mathbb{Q}(\mu)$.