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Although operator-valued kernels have recently received increasing interest in various machine learning and functional data analysis problems such as multi-task learning or functional regression, little attention has been paid to the…

Machine Learning · Computer Science 2013-01-15 Hachem Kadri , Asma Rabaoui , Philippe Preux , Emmanuel Duflos , Alain Rakotomamonjy

We found the optimal linear information and the optimal method of its use to recovery of the convolution of n functions on some classes of $2\pi$ - periodic functions.

Functional Analysis · Mathematics 2015-05-12 V. F. Babenko , M. S. Gunko

We prove that the optimal error of recovery in the $L_2$ norm of functions from a class $\bF$ can be bounded above by the value of the Kolmogorov width of $\bF$ in the uniform norm. We demonstrate on a number of examples of $\bF$ from…

Numerical Analysis · Mathematics 2020-10-08 V. Temlyakov

Under investigation is the problem of finding the best approximation of a function in a Hilbert space subject to convex constraints and prescribed nonlinear transformations. We show that in many instances these prescriptions can be…

Functional Analysis · Mathematics 2021-06-17 Patrick L. Combettes , Zev C. Woodstock

In this paper, stability and sensitivity properties of a class of parametric constrained optimization problem, whose feasible region is defined by a set-valued inclusion, are investigated through the associated optimal value function.…

Optimization and Control · Mathematics 2024-12-06 Amos Uderzo

The study of operator algebras on Hilbert spaces, and C*-algebras in particular, is one of the most active areas within Functional Analysis. A natural generalization of these is to replace Hilbert spaces (which are $L^2$-spaces) with…

Functional Analysis · Mathematics 2019-10-09 Eusebio Gardella

This current article aims to study a new subclass of meromorphic functions with positive coefficients by reconstructing a new operator in the punctured open disc. Also, some geometric properties are considered and investigated, such results…

Complex Variables · Mathematics 2024-08-16 Ali H. Maran , Abdul Rahman S. Juma , Raheam A. Al-Saphory

We study multivariate integration and approximation for functions belonging to a weighted reproducing kernel Hilbert space based on half-period cosine functions in the worst-case setting. The weights in the norm of the function space depend…

Numerical Analysis · Mathematics 2015-11-23 Christian Irrgeher , Peter Kritzer , Friedrich Pillichshammer

The present paper, is devoted to investigation of operator--valued Fourier multiplier theorems from $B_{q_{1},r}^{s}$ to $B_{q_{2},r}^{s}$, optimal embedding of Besov spaces, the separability and positivity of differential operators. Here,…

Functional Analysis · Mathematics 2008-08-20 Veli Shakhmurov , Rishad Shahmurov

In this paper, we prove optimal convergence rates results for regularisation methods for solving linear ill-posed operator equations in Hilbert spaces. The result generalises existing convergence rates results on optimality to general…

Functional Analysis · Mathematics 2015-11-11 Vinicius Albani , Peter Elbau , Maarten V. de Hoop , Otmar Scherzer

Free bondary value problem for elliptic differential-operator equations with variable coefficients is studied. The uniform maximal regularity properties and Fredholmness of this problem are obtained in vector-valued Holder spaces.

Analysis of PDEs · Mathematics 2017-06-06 Veli Shakhmurov

We consider optimal control problems with integer-valued controls and a total variation regularization penalty in the objective on domains of dimension two or higher. The penalty yields that the feasible set is sequentially closed in the…

Optimization and Control · Mathematics 2023-08-23 Paul Manns , Annika Schiemann

In this paper, we consider optimizing a smooth, convex, lower semicontinuous function in Riemannian space with constraints. To solve the problem, we first convert it to a dual problem and then propose a general primal-dual algorithm to…

Machine Learning · Computer Science 2020-05-20 Shijun Wang , Baocheng Zhu , Lintao Ma , Yuan Qi

Regularization techniques are widely employed in optimization-based approaches for solving ill-posed inverse problems in data analysis and scientific computing. These methods are based on augmenting the objective with a penalty function,…

Optimization and Control · Mathematics 2021-06-08 Yong Sheng Soh , Venkat Chandrasekaran

We show that every operator in $L^{2}$ has an associated measure on a space of functions and prove that it can be used to find solutions to abstract Cauchy problems, including partial differential equations. We find explicit formulas to…

Mathematical Physics · Physics 2024-09-06 Luis A. Cedeño-Pérez , Hernando Quevedo

Fuzzy relational inequalities with fuzzy constraints (FRI-FC) are the generalized form of fuzzy relational inequalities (FRI) in which fuzzy inequality replaces ordinary inequality in the constraints. Fuzzy constraints enable us to attain…

Optimization and Control · Mathematics 2023-09-12 Amin Ghodousian , Romina Omidi

An unsteady problem is considered for a space-fractional equation in a bounded domain. A first-order evolutionary equation involves the square root of an elliptic operator of second order. Finite element approximation in space is employed.…

Numerical Analysis · Mathematics 2015-10-29 Petr N. Vabishchevich

Some concepts, such as non-compactness measure and condensing operators, defined on metric spaces are extended to uniform spaces. Such extensions allow us to locate, in the context of uniform spaces, some classical results existing in…

General Topology · Mathematics 2015-11-25 Raúl Fierro

Let $X$ be a space of homogeneous type and $L$ be a nonnegative self-adjoint operator on $L^2(X)$ satisfying Gaussian upper bounds on its heat kernels. In this paper we develop the theory of weighted Besov spaces…

Functional Analysis · Mathematics 2018-09-11 Huy-Qui Bui , The Anh Bui , Xuan Thinh Duong

In this paper, we specify a set of optimal subspaces for $L_2$ approximation of three classes of functions in the Sobolev space $W^{(r)}_2$, defined on a segment and subject to certain boundary conditions. All of these subspaces are…

Classical Analysis and ODEs · Mathematics 2019-05-28 A. Yu. Ulitskaya , O. L. Vinogradov