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Related papers: On weak $I^K$-Cauchy sequences in normed spaces

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We consider the Cauchy problem for weakly hyperbolic $m$-th order partial differential equations with coefficients low-regular in time and smooth in space. It is well-known that in general one has to impose Levi conditions to get $C^\infty$…

Analysis of PDEs · Mathematics 2017-11-17 Daniel Lorenz , Michael Reissig

We extend the Koopman-von Neumann convergence condition on the Ces\`{a}ro mean to the context of a Dedekind complete Riesz space with weak order unit. As a consequence, a characterisation of conditional weak mixing is given in the Riesz…

Functional Analysis · Mathematics 2020-10-26 Jonathan Homann , Wen-Chi Kuo , Bruce A. Watson

We analyze weak convergence on CAT(0) spaces and the existence and properties of corresponding weak topologies.

Metric Geometry · Mathematics 2023-08-01 Alexander Lytchak , Anton Petrunin

We prove that if a unital Banach algebra $A$ is the dual of a Banach space $\pd{A}$, then the set of weak* continuous states is weak* dense in the set of all states on $A$. Further, weak* continuous states linearly span $\pd{A}$.

Functional Analysis · Mathematics 2008-08-15 Bojan Magajna

We introduce a notion of weak convergence in arbitrary metric spaces. Metric functionals are key in our analysis: weak convergence of sequences in a given metric space is tested against all the metric functionals defined on said space. When…

Functional Analysis · Mathematics 2025-06-05 Armando W. Gutiérrez , Olavi Nevanlinna

In these notes, we study nonlinear embeddings between Banach spaces which are also weakly sequentially continuous. In particular, our main result implies that if a Banach space $X$ coarsely (resp. uniformly) embeds into a Banach space $Y$…

Functional Analysis · Mathematics 2017-10-24 Bruno de Mendonça Braga

We investigate weak$^*$ derived sets, that is the sets of weak$^*$ limits of bounded nets, of convex subsets of duals of non-reflexive Banach spaces and their possible iterations. We prove that a dual space of any non-reflexive Banach space…

Functional Analysis · Mathematics 2021-11-29 Zdeněk Silber

This paper deals with the interplay of the geometry of the norm and the weak topology in Banach spaces. Both dual and intrinsic connections between weak forms of rotundity and smoothness ared discussed. Weakly exposed points, weakly locally…

Functional Analysis · Mathematics 2007-06-25 J. Talponen

In this paper, we consider a new weak norm, iterated weak norm in Lebesgue spaces with mixed norms. We study properties of the mixed weak norm and the iterated weak norm and present the relationship between the two weak norms. Even for the…

Functional Analysis · Mathematics 2018-04-02 Ting Chen , Wenchang Sun

In this paper we mainly investigate the Cauchy problem of a generalized Camassa-Holm equation. First by this relationship between the Degasperis-Procesi equation and the generalized Camassa-Holm equation, we then obtain two global…

Analysis of PDEs · Mathematics 2016-01-06 Xi Tu , Zhaoyang Yin

In this paper we have studied the ideas of I-divergence and I*-divergence of sequences in cone metric spaces. We have investigated the relationship between I-divergence and I*-divergence and their equivalence under certain condition.…

General Topology · Mathematics 2018-06-26 Amar Kumar Banerjee , Anirban Paul

We study the weakest convergence-type conditions for fixed point results for Banach and Kannan mappings. Building on Suzuki's weakest condition for Banach mappings and our previous result for Kannan mappings, we compare convergence…

Functional Analysis · Mathematics 2026-05-13 Shunya Hashimoto , Misako Kikkawa , Shuji Machihara , Aqib Saghir

Fixed point iterations are a fundamental tool in numerical analysis and scientific computing for the approximation of solutions to nonlinear problems. Their convergence is often established via the Banach fixed point theorem, provided that…

Numerical Analysis · Mathematics 2026-04-29 Thomas P. Wihler

In this paper we study the well-posedness of the Cauchy problem for a wave equation with multiplicities and space-dependent irregular coefficients. As in \cite{GR:14} in order to give a meaningful notion of solution, we employ the notion of…

Analysis of PDEs · Mathematics 2020-04-22 Claudia Garetto

In this paper, we study the Cauchy problem for a generalized two-component Novikov system with weak dissipation. We first establish the local well-posedness of solutions by using the Kato's theorem. Then we give the necessary and sufficient…

Analysis of PDEs · Mathematics 2025-08-07 Yonghui Zhou , Xiaowan Li , Shuguan Ji , Zhijun Qiao

In this paper using a non-negative regular summability matrix $\mathcal{A}$ and a non-trivial admissible ideal $\mathcal{I}$ in $\mathbb{N}$ we study some basic properties of strong $\mathcal{A}^{\mathcal{I}}$-statistical convergence and…

Functional Analysis · Mathematics 2022-08-08 Prasanta Malik , Samiran Das

In this paper, we study the ill-posdness of the Cauchy problem for semilinear wave equation with very low regularity, where the nonlinear term depends on $u$ and $\partial_t u$. We prove a ill-posedness result for the "defocusing" case, and…

Analysis of PDEs · Mathematics 2010-04-22 Daoyuan Fang , Chengbo Wang

In this paper, using Q*-closed sets, we introduce a new version of normality called, Q*-normality which is a weak form of normality. Further utilizing Q*g-closed sets, we obtain some characterizations of Q*-normal and normal spaces and also…

General Topology · Mathematics 2025-06-19 Hamant Kumar , Neeraj Kumar Tomar

We study the well-posedness of the Cauchy problem for a fractional porous medium equation with a varying density. We establish existence of weak energy solutions; uniqueness and nonuniqueness is studied as well, according with the behavior…

Analysis of PDEs · Mathematics 2013-02-04 Fabio Punzo , Gabriele Terrone

In this paper we study the Cauchy problem for the Landau Hamiltonian wave equation, with time dependent irregular (distributional) electromagnetic field and similarly irregular velocity. For such equations, we describe the notion of a `very…

Analysis of PDEs · Mathematics 2017-05-05 Michael Ruzhansky , Niyaz Tokmagambetov