8 citations · 14 across the 9 of their papers we have counts for
8 papers · 1 filter
Krein-Šmul'jan Theorem Revisited
Santiago gonzalez Zerbo, Alejandra Maestripieri, Francisco Martínez Pería
We present a generalization of Krein-Šmul'jan theorem which involves several operators. Given bounded selfadjoint operators acting on a Hilbert space $\mathcal{H…
Indefinite least squares with a quadratic constraint
Santiago Gonzalez Zerbo, Alejandra Maestripieri, Francisco Martínez Pería
An abstract indefinite least squares problem with a quadratic constraint is considered. This is a quadratic programming problem with one quadratic equality constraint, where neithe…
Linear pencils and quadratic programming problems with a quadratic constraint
Santiago Gonzalez Zerbo, Alejandra Maestripieri, Francisco Martínez Pería
Given bounded selfadjoint operators and acting on a Hilbert space , consider the linear pencil , . The set of parameters such th…
Regularization of an Indefinite Abstract Interpolation Problem with a Quadratic Constraint
Santiago Gonzalez Zerbo, Alejandra Maestripieri, Francisco Martínez Pería
Along this work we study an indefinite abstract smoothing problem. After establishing necessary and sufficient conditions for the existence of solutions to this problem, the set of…
On a class of non-Hermitian matrices with positive definite Schur complements
Thomas Berger, Juan Ignacio Giribet, Francisco Martínez Pería +1
Given a positive definite matrix and a Hermitian matrix , we characterize under which conditions there exists a strictly…
On the geometry of normal projections in Krein spaces
Eduardo Chiumiento, Alejandra Maestripieri, Francisco Martínez Pería
Let be a Krein space with fundamental symmetry . Along this paper, the geometric structure of the set of -normal projections is studied. The group…
The effect of finite rank perturbations on Jordan chains of linear operators
Jussi Behrndt, Leslie Leben, Francisco Martínez Pería +1
A general result on the structure and dimension of the root subspaces of a matrix or a linear operator under finite rank perturbations is proved: The increase of dimension from the…
On a family of frames for Krein spaces
J. I. Giribet, A. Maestripieri, F. Martínez Pería +1
A definition of frames for Krein spaces is proposed, which extends the notion of -orthonormal basis of Krein spaces. A -frame for a Krein space $(\HH, \K{\,}{\,})$ is in part…