Pairs of matrices, one of which commutes with their commutator.
Patterns of commutativity: the commutant of the full pattern.
Pencils of real symmetric matrices and the numerical range.
Periodic coprime matrix fraction decompositions.
Perturbations of functions of diagonalizable matrices.
Polynomial sequences generated by infinite Hessenberg matrices
We show that an infinite lower Hessenberg matrix generates polynomial sequences that correspond to the rows of infinite lower triangular invertible matrices. Orthogonal polynomial sequences are obtained when the Hessenberg matrix is tridiagonal. We study properties of the polynomial sequences and their corresponding matrices which are related to recurrence relations, companion matrices, matrix similarity, construction algorithms, and generating functions. When the Hessenberg matrix is also Toeplitz...
Primary decomposition of torsion -modules.
Pseudo-similarity and partial unit regularity