How to establish universal block-matrix factorizations
Yongge Tian, George P. H. Styan · Electronic Journal of Linear Algebra · 2001
A general method is presented for establishing universal factorization equalities for 2× 2a nd 4×4 block matrices. As applications, some universal factorization equalities for matrices over four-dimensional algebras are established, in particular, over the Hamiltonian quaternion algebra.