Let H be a separable Hilbert space, and let D(B(H) ah) be the antiHermitian bounded diagonal operators in some fixed orthonormal basis and K(H) the compact operators. We study the group of unitary operators Uk,d = {u ∈ ...

In the present paper, we study the unitary orbit of a compact Hermitian diagonal operator with spectral multiplicity one under the action of the unitary group U(K+C) of the unitization of the compact operators K(H) + C, ...

We study some examples of minimal length curves in homogeneous spaces of B(H) under a left action of a unitary group. Recent results relate these curves with the existence of minimal (with respect to a quotient norm) ...

We study those orbits of oblique projections under the action of the full unitary group of a Hilbert space H, which are submanifolds of B(H). We also consider orbits under the Schatten unitaries, and obtain a partial ...

Let A ⊆ Mn(C) be a unital ∗-subalgebra of the algebra Mn(C) of all n×n complex matrices and let B be an hermitian matrix. Let Un(B) denote the unitary orbit of B in Mn(C) and let EA denote the trace preserving conditional ...