Idempotent matrices
Source: IMS 2008
May 10, 2008
inductionLaTeXlinear algebramatrixalgebrapolynomial
Problem Statement
Let be idempotent matrices with real entries. Prove that:
\mbox{N}(A_1)\plus{}\mbox{N}(A_2)\plus{}\dots\plus{}\mbox{N}(A_n)\geq \mbox{rank}(I\minus{}A_1A_2\dots A_n)
\mbox{N}(A) is \mbox{dim}(\mbox{ker(A)})