ELA, Volume 16, pp. 162-170, July 2007, abstract.
On Nonnegative Sign Equivalent and Sign Similar
Factorizations of Matrices
Daniel Hershkowitz and Allan Pinkus
It is shown that every real nxn matrix is a product of
at most two nonnegative sign equivalent matrices, and
every real nxn matrix, n>=2, is a product of at most three
nonnegative sign similar matrices. Finally, it is proved
that every real nxn matrix is a product of totally positive
sign equivalent matrices. However, the question of the
minimal number of such factors is left open.