Results 51 to 60 of about 8,503 (184)
Characterizing Riesz Bases via Biorthogonal Riesz-Fischer sequences
, 2022 In this note we prove that if two Riesz-Fischer sequences in a separable Hilbert space $H$ are biorthogonal and one of them is complete in $H$, then both sequences are Riesz bases for $H$. This complements a recent result by D. T. Stoeva where the same conclusion holds if one replaces the phrase ``Riesz-Fischer sequences'' by ``Bessel sequences''.
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On Construction of Bounded Sets Not Admitting a General Type of Riesz Spectrum
AxiomsWe construct a bound set that does not admit a Riesz spectrum containing a nonempty periodic set for which the period is a rational multiple of a fixed constant.
Dae Gwan Lee
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Non-self-adjoint hamiltonians defined by Riesz bases [PDF]
Journal of Mathematical Physics, 2014 We discuss some features of non-self-adjoint Hamiltonians with real discrete simple spectrum under the assumption that the eigenvectors form a Riesz basis of Hilbert space. Among other things, we give conditions under which these Hamiltonians can be factorized in terms of generalized lowering and raising operators.
Bagarello, F., Inoue, A., Trapani, C.
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A quantitative Balian-Low theorem
, 2012 We study functions generating Gabor Riesz bases on the integer lattice. The classical Balian-Low theorem restricts the simultaneous time and frequency localization of such functions.
Nitzan, Shahaf, Olsen, Jan-Fredrik
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Financial Statement Information and Equity Value: The Role of Real Options Characteristics
Financial Management, EarlyView.ABSTRACT This paper examines whether firm‐specific real options characteristics are equity value‐relevant beyond valuation estimates anchored in financial statements. Using extensive historical data for the United Kingdom, we assess and compare the forecast accuracy and explanatory power for stock prices of equity valuation models based on residual ...
Mingyu (Chandler) Chen +2 more
wiley +1 more source
Riesz bases, Meyer’s quasicrystals, and bounded remainder sets [PDF]
Transactions of the American Mathematical Society, 2018 We consider systems of exponentials with frequencies belonging to simple quasicrystals in $\mathbb{R}^d$. We ask if there exist domains $S$ in $\mathbb{R}^d$ which admit such a system as a Riesz basis for the space $L^2(S)$. We prove that the answer depends on an arithmetical condition on the quasicrystal.
Grepstad, Sigrid, Lev, Nir
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Spatial depth for data in metric spaces
Scandinavian Journal of Statistics, EarlyView.Abstract We propose a novel measure of statistical depth, the metric spatial depth, for data residing in an arbitrary metric space. The measure assigns high (low) values for points located near (far away from) the bulk of the data distribution, allowing quantifying their centrality/outlyingness.
Joni Virta
wiley +1 more source
Some relationship between G-frames and frames [PDF]
Sahand Communications in Mathematical Analysis, 2015 In this paper we proved that every g-Riesz basis for Hilbert space $H$ with respect to $K$ by adding a condition is a Riesz basis for Hilbert $B(K)$-module $B(H,K)$. This is an extension of [A. Askarizadeh,M. A.
Mehdi Rashidi-Kouchi, Akbar Nazari
doaj
Riesz bases of reproducing kernels in Fock type spaces
, 2009 In a scale of Fock spaces $\mathcal F_\varphi$ with radial weights $\varphi$ we study the existence of Riesz bases of (normalized) reproducing kernels. We prove that these spaces possess such bases if and only if $\varphi(x)$ grows at most like $(\log x)^
Borichev, A., Lyubarskii, Yu.
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Building a Digital Twin for Material Testing: Model Reduction and Data Assimilation
Proceedings in Applied Mathematics and Mechanics, Volume 26, Issue 2, June 2026.ABSTRACT The rapid advancement of industrial technologies, data collection, and handling methods has paved the way for the widespread adoption of digital twins (DTs) in engineering, enabling seamless integration between physical systems and their virtual counterparts.
Rubén Aylwin +5 more
wiley +1 more source