I have a matrix $A$ which is strictly lower triangular. Now, I am trying to find some general statements/relationships of following matrices $U,D,V,K$ defined as:
$AA^T=VKV^H$,
$[(I-A)(I-A)^T]^{-1}=UD^{-1}U^H$
Is it possible to put $D$ and $K$ into some relations and also $U$ and $V$? From simple examples it is possible to see much structure between $AA^T$ and $[(I-A)(I-A)^T)]^{-1}$, however, in "Matrix Analysis" by Horn & Johnson I was not able to find something useful for this case. Maybe someone has some great idea!
Many thanks in advance!