ELA, Volume 12, pp. 17-24, January 2005, abstract.

Positive Entries of Stable Matrices

Shmuel Friedland, Daniel Hershkowitz, and 
Siegfried M. Rump

The question of how many elements of a real 
positive stable matrix must be positive is 
investigated. It is shown that any real stable
matrix of order greater than 1 has at least two 
positive entries. Furthermore, for every stable 
spectrum of cardinality greater than 1 there 
exists a real matrix with that spectrum with 
exactly two positive elements, where all other 
elements of the matrix can be chosen to be negative.