Completely positive matrix
= Completely positive matrix
{title2=$B=\sum_jx_jx_j^T,\ x_j\geq0$}
A real <symmetric matrix> admitting a finite sum of nonnegative <rank-one matrices> $x_jx_j^T$. It is both a <positive semidefinite matrix> and a <nonnegative matrix>, but these two properties alone need not imply membership in the <completely positive cone> in arbitrary <dimension>. This <matrix> notion is distinct from a <completely positive map>.