Unitary completions of complex symmetric and skew symmetric matrices.
Unitary similarity of algebras generated by pairs of orthoprojectors.
Unitary similarity of projectors.
Universal bounds for matrix semigroups
We show that any compact semigroup of n × n matrices is similar to a semigroup bounded by √n. We give examples to show that this bound is best possible and consider the effect of the minimal rank of matrices in the semigroup on this bound.
Universal bounds for positive matrix semigroups
We show that any compact semigroup of positive n × n matrices is similar (via a positive diagonal similarity) to a semigroup bounded by √n. We give examples to show this bound is best possible. We also consider the effect of additional conditions on the semigroup and obtain improved bounds in some cases.
Universal factorization equalities over generalized quaternion algebras.
Universality in the random matrix spectra in the regime of weak non-hermiticity
Universally optimal matrices and field independence of the minimum rank of a graph.
Untersuchungen über quadratische Formen in Körpern der Charakteristik 2.
Upon the generalised inverse of a formal power series with vector valued coefficients
Upper bound for the non-maximal eigenvalues of irreducible nonnegative matrices
We present a lower and an upper bound for the second smallest eigenvalue of Laplacian matrices in terms of the averaged minimal cut of weighted graphs. This is used to obtain an upper bound for the real parts of the non-maximal eigenvalues of irreducible nonnegative matrices. The result can be applied to Markov chains.
Upper bounds for the abscissa of stability of a stable matrix
Upper bounds for the best normal approximation.
Upper bounds on certain functionals defined on groups of linear operators.
Upper bounds on the solution of coupled algebraic Riccati equation.
Use of the interior-point method for correcting and solving inconsistent linear inequality systems.
Using linear programming in Petri net analysis