Browsing by Author "Pothen, Alex"
Coleman, Thomas F.; Pothen, Alex (Cornell University, 1986-04)The Null Space Problem is that of finding a sparsest basis for the null space (null basis) of a $t \times n$ matrix of rank $t$. This problem was shown to be NP-hard in Coleman and Pothen (1985). In this paper we develop ...
Coleman, Thomas F.; Pothen, Alex (Cornell University, 1984-07)The sparse null space basis problem is the following: $A t \times n$ matrix $A (t less than n)$ is given. Find a matrix $N$, with the fewest nonzero entries in it, whose columns span the null space of $A$. This problem ...