Reading:On Matrix decomposition

On Matrix decomposition

In order to complete the previous post on unitary matrix decomposition (sum) , I give here two interesting links about other known matrix decomposition :

In quantum physics we love to use unitary operations, so here are the decompositions involving unitary matrices. We have U,V unitary, T,R triangular, Q orthogonal and D diagonal :

Do you use other useful unitary decomposition?