If it's linear algebra and it's combinatorics, then you have my attention...
14 How far is a set of vectors from being orthogonal? may 18 '12
7 How few terms may appear in a polynomial with given (cyclotomic) roots and nonnegative coefficients? aug 12 '13
7 elementwise functions of positive definite matrix jul 20 '14
3 New base of matroid from olds sep 21
2 Find base of kernel with as many 0 as possible aug 22 '14