# 05C50 Online Seminar: Kevin Vander Meulen

## Topic

On counting eigenvalues of a matrix sign pattern

## Details

The signs of the entries of a real matrix can give insight into the eigenvalues of the matrix. A well-known example is the Perron Frobenius theorem for matrices that have no negative entries. As an inverse eigenvalue problem, one can ask for the possible spectra of a given sign pattern, where a sign pattern is a specified arrangement of the zero, positive and negative entries. We review combinatorial and analytic techniques employed to explore the possible spectra of a sign pattern. We present recent results, and open questions, on the number of distinct eigenvalues allowed by a sign pattern.

*This talk will NOT be recorded. You may email the speaker for their slides.*

## Additional Information

The 05C50 Online is an international seminar about graphs and matrices held twice a month on Fridays.

**Time: 8AM Pacific/10AM Central **

For more information, visit __https://sites.google.com/view/05c50online/home__.

If you would like to attend, please register using this form to receive the zoom links: __https://docs.google.com/forms/d/e/1FAIpQLSdQ98fh58cgeSWzbFe3t77i28FXDck1gYuX9jv_qd4kEf5l_Q/viewform?usp=sf_link__

**Scientific, Seminar**

**October 11, 2024**

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