Linear algebra, matrix analysis, matrix theory, eigenvalue problems, inverse problems, numerical analysis, polynomial matrices, rational matrices.
My current research interest is in the area of nonlinear eigenvalue problems and their applications. Inverse eigenvalues problems and matrix factorizations in applications as well as in theory, general matrix theory.
"Van Dooren's Index Sum Theorem and Rational Matrices with Prescribed Structural Data", SIAM J. Matrix Anal. Appl., 40(2), 720-738.