Zobrazeno 1 - 10
of 71
pro vyhledávání: '"Chiumiento, Eduardo"'
We study the action of Bogoliubov transformations on admissible generalized one-particle density matrices arising in Hartree-Fock-Bogoliubov theory. We show that the orbits of this action are reductive homogeneous spaces, and we give several equivale
Externí odkaz:
http://arxiv.org/abs/2402.15606
Autor:
Chiumiento, Eduardo, Massey, Pedro
We study the Moore-Penrose inverse of perturbations by a symmetrically-normed ideal of a closed range operator on a Hilbert space. We show that the notion of essential codimension of projections gives a characterization of subsets of such perturbatio
Externí odkaz:
http://arxiv.org/abs/2312.02693
Autor:
Chiumiento, Eduardo, Massey, Pedro
Let $\mathcal{H}$ be a separable infinite-dimensional complex Hilbert space and let $\mathcal{J}$ be a two-sided ideal of the algebra of bounded operators $\mathcal{B}(\mathcal{H})$. The groups $\mathcal{G} \ell_\mathcal{J}$ and $\mathcal{U}_{\mathca
Externí odkaz:
http://arxiv.org/abs/2307.01959
Autor:
Chiumiento, Eduardo, Massey, Pedro
Let $\mathcal{H}$ be a separable infinite-dimensional complex Hilbert space, $\mathcal{B}(\mathcal{H})$ the algebra of bounded linear operators acting on $\mathcal{H}$ and $\mathcal{J}$ a proper two-sided ideal of $\mathcal{B}(\mathcal{H})$. Denote b
Externí odkaz:
http://arxiv.org/abs/2106.06612
Autor:
Chiumiento, Eduardo
The polar factor of a bounded operator acting on a Hilbert space is the unique partial isometry arising in the polar decomposition. It is well known that the polar factor might not be a best approximant to its associated operator in the set of all pa
Externí odkaz:
http://arxiv.org/abs/2106.01825
Let $\mathcal{H}$ be a reproducing kernel Hilbert space of functions on a set $X$. We study the problem of finding a minimal geodesic of the Grassmann manifold of $\mathcal{H}$ that joins two subspaces consisting of functions which vanish on given fi
Externí odkaz:
http://arxiv.org/abs/2007.16181
We study the elementary C*-algebra whose elements are the sum of a diagonal plus a compact operator. We describe the structure of the unitary group, the sets of ideals, automorhisms and projections.
Comment: 24 pages
Comment: 24 pages
Externí odkaz:
http://arxiv.org/abs/1903.06102
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For a given Hilbert space $\mathcal H$, consider the space of self-adjoint projections $\mathcal P(\mathcal H)$. In this paper we study the differentiable structure of a canonical sphere bundle over $\mathcal P(\mathcal H)$ given by $$ \mathcal R=\{\
Externí odkaz:
http://arxiv.org/abs/1803.01057
Autor:
Chiumiento, Eduardo
We solve the problem of best approximation by Parseval frames to an arbitrary frame in a subspace of an infinite dimensional Hilbert space. We explicitly describe all the solutions and we give a criterion for uniqueness. This best approximation probl
Externí odkaz:
http://arxiv.org/abs/1711.08543