On structured perturbation of Hermitian matrices Original Research Article

This paper concerns a quantity which is equal to the norm of the smallest structured perturbation to a Hermitian matrix that makes the perturbed matrix singular. This quantity of course then gives an indication on how much such structured perturbation the Hermitian matrix can tolerate before becoming singular. For some structures, this quantity can be computed explicitly. For some more general structures, only the lower bound on this quantity is given.