Continuous weaving fusion frames in Hilbert spaces

Generalized frames (in short, $g$-frames) are a natural generalization of standard frames in separable Hilbert spaces. Motivated by the concept of weaving frames in separable Hilbert spaces by Bemrose, Casazza, Grochenig, Lammers and Lynch in the context of distributed signal processing, we study weaving properties of $g$-frames. Firstly, we present necessary and sufficient con\-ditions for weaving $g$-frames in Hilbert spaces. We extend some results of \cite Bemrose, Casazza, Grochenig, Lammers and Lynch, and Casazza and Lynch regarding conversion of standard weaving frames to $g$-weaving frames. Some Paley-Wiener type perturbation results for weaving $g$-frames are obtained. Finally, we give necessary and sufficient conditions for weaving $g$-Riesz bases.

Continuous Frames in Hilbert Space

In this paper, we first introduce the notion of controlled weaving [Formula: see text]-[Formula: see text]-frames in Hilbert spaces. Then, we present sufficient conditions for controlled weaving [Formula: see text]-[Formula: see text]-frames in separable Hilbert spaces. Also, a characterization of controlled weaving [Formula: see text]-[Formula: see text]-frames is given in terms of an operator. Finally, we show that if bounds of frames associated with atomic spaces are positively confined, then controlled [Formula: see text]-[Formula: see text]-woven frames give ordinary weaving [Formula: see text]-frames and vice-versa.

Continuous frames and fusion frames were considered recently as generalizations of frames in Hilbert spaces. In this paper, for any continuous fusion frame, we obtain a new family of inequalities which are parametrized by a parameter $$\lambda \in \mathbb {R}$$ . By suitable choices of $$\lambda $$ , one obtains the previous results as special cases. Moreover, these new inequalities involve the expressions $$\langle S_Yh,h \rangle $$ , $$\Vert S_Yh\Vert $$ , etc., where $$S_Y$$ is a “truncated form” of the continuous fusion frame operator.

The study of the c$k$-fusions frames shows that the emphasis on the measure spaces introduces a new idea, although some similar properties with the discrete case are raised. Moreover, due to the nature of measure spaces, we have to use new techniques for new results. Especially, the topic of the dual of frames which is important for frame applications, have been specified completely for the continuous frames. After improving and extending the concept of fusion frames and continuous frames, in this paper we introduce continuous $k$-fusion frames in Hilbert spaces. Similarly to the c-fusion frames, dual of continuous $k$-fusion frames may not be defined, we however define the $Q$-dual of continuous $k$-fusion frames. Also some new results and the perturbation of continuous $k$-fusion frames will be presented.

G-frames, which include many generalizations of frames such as frames of subspaces or fusion frames, oblique frames, and pseudo-frames, are natural generalizations of frames in Hilbert spaces. They have some properties similar to those of frames in Hilbert spaces, but not all of their properties are similar. For example, exact frames are equivalent to Riesz bases, but exact g-frames are not equivalent to g-Riesz bases. Some authors have extended the equalities and inequalities for frames and dual frames to g-frames and dual g-frames in Hilbert spaces. In this paper, we establish some new equalities and inequalities for g-Bessel sequences or g-frames in Hilbert spaces. We also give a necessary and sufficient condition that the equality occurs in one of these inequalities. Our results generalize and improve the remarkable results which had been obtained by Balan, Casazza and Gavruta.

Some equalities and inequalities for <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.gif" display="inline" overflow="scroll"><mml:mi>g</mml:mi></mml:math>-Bessel sequences in Hilbert spaces

Improving and extending the concept of dual for frames, fusion frames and continuous frames, the notion of dual for continuous fusion frames in Hilbert spaces will be studied. It will be shown that generally the dual of c-fusion frames may not be defined. To overcome this problem, the new concept namely Q-dual for c-fusion frames will be defined and some of its properties will be investigated.

Disjointness of frames in Hilbert spaces is closely related with superframes in Hilbert spaces and it also plays an important role in construction of superframes and frames, which were introduced and studied by Han and Larson. \(G\)-frame is a generalization of frame in Hilbert spaces, which covers many recent generalizations of frame in Hilbert spaces. In this paper, we study the \(g\)-frames in Hilbert spaces. We focus on the characterizations of disjointness of \(g\)-frames and constructions of \(g\)-frames. All types of disjointness are firstly characterized in terms of disjointness of frames induced by \(g\)-frames, then are characterized in terms of certain orthogonal projections. Finally we use disjoint \(g\)-frames to construct \(g\)-frames.

In this paper, we introduce and characterize controlled dual frames in Hilbert spaces. We also investigate the relation between bounds of controlled frames and their related frames. Then, we define the concept of approximate duality for controlled frames in Hilbert spaces. Next, we introduce multiplier operators of controlled frames in Hilbert spaces and investigate some of their properties. Finally, we show that the inverse of a controlled multiplier operator is also a controlled multiplier operator under some mild conditions.

The material presented in this book naturally splits in two parts: a functional analytic treatment of frames in general Hilbert spaces, and a more direct approach to structured frames like Gabor frames and wavelet frames. For the second part the most general results were presented in Chapter 21, in the setting of generalized shift-invariant systems on an LCA group.The current chapter is in a certain sense a natural continuation of both tracks. We consider connections between frame theory and abstract harmonic analysis and show how we can construct frames in Hilbert spaces via the theory for group representations. In special cases the general approach will bring us back to the Gabor systems and wavelet systems. The abstract framework adds another new aspect to the theory: we will not only obtain expansions in Hilbert spaces but also in a class of Banach spaces.

In this paper, we begin with the classical concept of tight frames in Hilbert spaces. First, we introduce the orthogonal projection P between H and θ(H) (the range of the frame transform θ associated with a traditional tight frame) and investigate the relationship between P and θ. We then explore fusion frames and extend the index set to an infinite set through a concrete example. Second, we examine the role of orthogonal projections in fusion frames with particular emphasis on robustness and redundancy illustrated by examples. Finally, we study dual fusion frames and establish several important results, especially concerning the relationship between the frame operators of two types of dual fusion frames.

K-frames, a new generalization of frames, were recently considered by L. G\(\breve{\text {a}}\)vruţa in connection with atomic systems and some problems arising in sampling theory. Also, fusion frames are an important generalization of frames, applied in a variety of applications. In the present paper, we introduce the notion of K-fusion frames in Hilbert spaces and obtain several approaches for identifying of K-fusion frames. The main purpose is to reconstruct the elements from the range of the bounded operator K on a Hilbert space \(\mathcal {H}\) by using a family of closed subspaces in \(\mathcal {H}\). This work will be useful in some problems in sampling theory which are processed by fusion frames. For this end, we present some descriptions for duality of K-fusion frames and also resolution of the operator K to provide simple and concrete constructions of duals of K-fusion frames. Finally, we survey the robustness of K-fusion frames under some perturbations.

In this paper, we study continuous frames in Hilbert spaces using a family of linearly independent vectors called coherent state (CS) and applying it in any physical space. To accomplish this goal, the standard theory of frames in Hilbert spaces, using discrete bases, is generalized to one where the basis vectors may be labeled using discrete, continuous or a mixture of the two types of indices.&nbsp; A comprehensive analysis of such frames is presented and illustrated by the examples drawn from a toy example Sea Star and the affine group. Key words: Frame, continuous frame, unitary representation, coherent state (CS), sea star, affine group. &nbsp

Recently, fusion frames and frames for operators were considered as generalizations of frames in Hilbert spaces. In this paper, we generalize some of the known results in frame theory to fusion frames related to a linear bounded operator K which we call K-fusion frames. We obtain new K-fusion frames by considering K-fusion frames with a class of bounded linear operators and construct new K-fusion frames from given ones. We also study the stability of K-fusion frames under small perturbations. We further give some characterizations of atomic systems with subspace sequences.