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Related papers: Another proof of the analytic Hahn-Banach Theorem

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In this paper, we introduce a new subclass of close-to-convex harmonic functions. We present a sufficient coefficient condition for a function to be a member of this class. Furthermore, we establish a distortion theorem. These results lay…

Complex Variables · Mathematics 2025-02-10 Serkan Çakmak , Sibel Yalçin

In this technical note we provide a simple proof of Nehari's theorem on the optimal approximation by $H_\infty$ functions, based on convex duality.

Functional Analysis · Mathematics 2025-07-02 Cristian R. Rojas

We show a new, elementary and geometric proof of the classical Alexandrov theorem about the second order differentiability of convex functions. We also show new proofs of recent results about Lusin approximation of convex functions and…

Classical Analysis and ODEs · Mathematics 2023-08-02 Daniel Azagra , Anthony Cappello , Piotr Hajłasz

[REVISED VERSION] The aim of this paper is to state a sharp version of the K\"onig supremum theorem, an equivalent reformulation of the Hahn--Banach theorem. We apply it to derive statements of the Lagrange multipliers, Karush-Kuhn-Tucker…

Functional Analysis · Mathematics 2017-04-24 P. Montiel Lopez , M. Ruiz Galan

We analyze matrix convex functions of a fixed order defined on a real interval by differential methods as opposed to the characterization in terms of divided differences given by Kraus. We obtain for each order conditions for matrix…

Operator Algebras · Mathematics 2007-05-23 Frank Hansen , Jun Tomiyama

We prove an analytic KAM-Theorem, which is used in [1], where the differential part of KAM-theory is discussed. Related theorems on analytic KAM-theory exist in the literature (e. g., among many others, [7], [8], [13]). The aim of the…

Symplectic Geometry · Mathematics 2007-05-23 Joachim Albrecht

We present a simple geometric construction for smoothing polyhedral utility functions. Keywords: Afriat- Varian theorem, the utility function, the economic indices theory, convex analysis.

Optimization and Control · Mathematics 2007-05-23 S. Tarasov , A. Shananin

In this paper, we prove an operator version of the Jensen's inequality and its converse for $h$-convex functions. We provide a refinement of the Jensen type inequality for $h$-convex functions. Moreover, we prove the Hermite-Hadamard's type…

Functional Analysis · Mathematics 2022-01-19 Ismail Nikoufar , Davuod Saeedi

We prove that the coordinate functionals associated with filter bases in Banach spaces are continuous as long as the underlying filter is analytic. This removes the large-cardinal hypothesis from the result established by the two last-named…

Functional Analysis · Mathematics 2022-03-30 Noé de Rancourt , Tomasz Kania , Jarosław Swaczyna

First we recall the notion of conxity and log-convexity for real-valued. Then we generalize the trick used by Artin in his famous paper on the Gamma function to find log-convex solutions to the functional equations f(x+1)=g(x)f(x). This…

Classical Analysis and ODEs · Mathematics 2014-08-29 Martin Himmel

In this paper we established new integral inequalities which are more general results for coordinated convex functions on the coordinates by using some classical inequalities.

Classical Analysis and ODEs · Mathematics 2011-07-21 M. Emin Ozdemir , Cetin Yildiz , Ahmet Ocak Akdemir

We introduce the concept of shifting distance functions, and we establish a new fixed point theorem which generalizes the Banach contraction principle. An example is provided to illustrate our result.

Classical Analysis and ODEs · Mathematics 2013-10-04 Maher Berzig

As a first step towards a general set-theoretic counterpart of the remarkable Bernstein-Walsh-Siciak Theorem concerning the rapidity of polynomial approximation of a holomorphic function on polynomially convex compact sets in…

Complex Variables · Mathematics 2019-01-03 Anna Denkowska , Maciej P. Denkowski

Among other things, we show that the ideal sheaf of a complex Hilbert submanifold of a pseudoconvex open subset of Hilbert space is acyclic over the ambient pseudoconvex open set. We also prove a vanishing theorem for a fairly general class…

Complex Variables · Mathematics 2007-05-23 Imre Patyi

In this paper, we prove some new inequalities of Hadamard-type for convex functions on the co-ordinates.

Classical Analysis and ODEs · Mathematics 2012-03-21 M. Emin Ozdemir , Ahmet Ocak Akdemir , Mevlut Tunc

The paper studies semi-almost periodic holomorphic functions on a polydisk which have, in a sense, the weakest possible discontinuities on the boundary torus. The basic result used in the proofs is an extension of the classical Bohr…

Complex Variables · Mathematics 2008-12-19 A. Brudnyi , D. Kinzebulatov

In this paper we present short algebraic proofs of the Linear Conway--Gordon--Sachs and the Linear van Kampen--Flores theorems in the spirit of the Radon theorem on convex hulls. {\bf Theorem.} {\it Take any $n+3$ general position points in…

Combinatorics · Mathematics 2015-08-14 Ilya I. Bogdanov , Alexander D. Matushkin

We establish conditions for the discrete versions of logarithmic concavity and convexity of the higher order regularized basic hypergeometric function with respect simultaneous shift of all its parameters. For a particular case of Heine's…

Classical Analysis and ODEs · Mathematics 2018-08-16 S. I. Kalmykov , D. B. Karp

We present a proof of Hadamard Inverse Function Theorem by the methods of Variational Analysis, adapting an idea of I. Ekeland and E. Sere.

Functional Analysis · Mathematics 2024-08-05 Milen Ivanov , Nadia Zlateva

Let $k$ be a local field with valuation ring $O_k$ and residue field $\overline{k}$. We extend Hahn--Banach theorem for the class of seminormed $k$-vector spaces to several classes of locally convex spaces and subspaces over $k$, $O_k$, and…

Number Theory · Mathematics 2016-03-23 Tomoki Mihara
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