3 papers
math.FA2014
Construction, Extension and Coupling of Frames on Finite Dimensional Pontryagin Space
German Escobar, Kevin Esmeral, Osmin Ferrer
In this paper we extend to finite-dimensional Pontryagin spaces the methods used in \cite{CasazzaLeon,Deguang} to build frames from an adjoint and positive operator. It is proved t…
math.FA2013
Frames of subspaces in Hilbert spaces with -metrics
Primitivo Acosta-Humánez, Kevin Esmeral, Osmin Ferrer
If $\left(\h,\langle\cdot,\cdot\rangle\right)$ is a Hilbert space and on it we consider the sesquilinear form so-called -metric, where $W^{*}=W\in…
math.FA2013
Frames in Krein spaces arising from a non-regular W-metric
Kevin Esmeral, Osmin Ferrer, Elmar Wagner
A definition of frames in Krein spaces is stated and a complete characterization is given by comparing them to frames in the associated Hilbert space. The basic tools of frame theo…