The Gershgorin Disk Theorem is a very simple result that allows you to quickly make some deductions about the eigenvalues of a matrix. The post's author notes despite its simplicity it is rarely mentioned in introductory linear algebra courses. That was the case for me too - I never heard of it until I was in grad school.

## truth

from the always great xkcd

05:49 in General Commentary, math | Permalink | Comments (0)