4
votes
0answers
138 views
+150
Checking whether an element is in all inclusion-wise maximal common independent sets of two matroids
Given two matroids $M$ and $M'$ over the same universe $E$, and some element $x \in E$, I am interested in the importance of $x$ for the intersection (the common independent sets) …
6
votes
5answers
762 views
+100
Another colored balls puzzle (part II)
The same colleague as in http://mathoverflow.net/questions/130489/another-colored-balls-puzzle asked me the following variant which she called "part II".
Imagine you have $n$ ball …
13
votes
2answers
495 views
+150
Minimum off-diagonal elements of a matrix with fixed eigenvalues
Hello,
I am en engineer working in radar research. I came accross a problem I cannot seem to find math literature on it.
I can ask it in two different ways. Perhaps depending on …
