Results 71 to 80 of about 1,296 (214)
The weak (1,1) boundedness of Fourier integral operators with complex phases
Journal of the London Mathematical Society, Volume 113, Issue 3, March 2026.Abstract Let T$T$ be a Fourier integral operator of order −(n−1)/2$-(n-1)/2$ associated with a canonical relation locally parametrised by a real‐phase function. A fundamental result due to Seeger, Sogge and Stein proved in the 90's gives the boundedness of T$T$ from the Hardy space H1$H^1$ into L1$L^1$. Additionally, it was shown by T.
Duván Cardona, Michael Ruzhansky
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Dimer models and conformal structures
Communications on Pure and Applied Mathematics, Volume 79, Issue 2, Page 340-446, February 2026.Abstract Dimer models have been the focus of intense research efforts over the last years. Our paper grew out of an effort to develop new methods to study minimizers or the asymptotic height functions of general dimer models and the geometry of their frozen boundaries.
Kari Astala +3 more
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New Characterizations of Riesz Bases
, 1997 We give two equivalent conditions under which a frame is a Riesz basis of a separable Hilbert space and obtain formulas of Riesz bounds in terms of the eigenvalues of the Gram matrices of finite ...
Lim, Jae Kun, Kim, Hong Oh
core +1 more source
International Journal of Mathematics and Mathematical Sciences, 2012 Almost orthogonal frames have been introduced and studied. It has been proved that a bounded almost orthogonal frame satisfies Feichtinger conjecture. Also, we prove that a bounded almost orthogonal frame contains a Riesz basis.
Virender, A. Zothansanga, S. K. Kaushik
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A Choquet theory of Lipschitz‐free spaces
Proceedings of the London Mathematical Society, Volume 132, Issue 2, February 2026.Abstract Let (M,d)$(M,d)$ be a complete metric space and let F(M)$\mathcal {F}({M})$ denote the Lipschitz‐free space over M$M$. We develop a ‘Choquet theory of Lipschitz‐free spaces’ that draws from the classical Choquet theory and the De Leeuw representation of elements of F(M)$\mathcal {F}({M})$ (and its bi‐dual) by positive Radon measures on βM ...
Richard J. Smith
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Characterizing the R-duality of g-frames
Journal of Inequalities and Applications, 2019 In this paper, we define the g-Riesz-dual of a given special operator-valued sequence with respect to g-orthonormal bases for a separable Hilbert space.
Liang Li, Pengtong Li
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Plank theorems and their applications: A survey
Bulletin of the London Mathematical Society, Volume 58, Issue 1, January 2026.Abstract Plank problems concern the covering of convex bodies by planks in Euclidean space and are related to famous open problems in convex geometry. In this survey, we introduce plank problems and present surprising applications of plank theorems in various areas of mathematics.
William Verreault
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Electronic Journal of Differential Equations, 2001 We find sufficient conditions for systems of functions to be Riesz bases in $L_2(0,1)$. Then we improve a theorem presented in [13] by showing that a ``standard'' system of solutions of a nonlinear boundary-value problem, normalized to 1, is a Riesz ...
Peter E. Zhidkov
doaj
Karpatsʹkì Matematičnì Publìkacìï, 2019 In this article we investigate a problem with nonlocal boundary conditions which are multipoint perturbations of mixed boundary conditions in the unit square $G$ using the Fourier method. The properties of a generalized transformation operator $R: L_2(G)
Ya.O. Baranetskij +3 more
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Journal of Applied Mathematics, Volume 2026, Issue 1, 2026.The Lucas collocation approach is used in this study to approximate a fractional‐order financial crime model (FOFCM) numerically. The model categorizes the population into five groups: persons without a financial criminal past, those inclined toward financial crimes, active participants, individuals undergoing prosecution, and those imprisoned.
Mahmoud Abd El-Hady +4 more
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