Results 41 to 50 of about 560 (182)

Nonlocal multipoint problem for a differential equation of $2n$-th order with operator coefficients

Karpatsʹkì Matematičnì Publìkacìï, 2021
In the article, the spectral properties of a multipoint problem for a differential operator equation of order $2n$ are studied. The operator of the problem has an infinite number of multiple eigenvalues.
Ya.O. Baranetskij, I.I. Demkiv, A.V. Solomko, O.M. Sus'   +3 more
doaj   +1 more source

Decomposition theorem and Riesz basis for axisymmetric potentials in the right half-plane [PDF]

European Journal of Mathematics, 2015
The Weinstein equation with complex coefficients is the equation governing generalized axisymmetric potentials (GASP) which can be written as $L_m[u]=Δu+\left(m/x\right)\partial_x u =0$, where $m\in\mathbb{C}$. We generalize results known for $m\in\mathbb{R}$ to $m\in\mathbb{C}$.
Chaabi, Slah, Rigat, Stéphane
openaire   +2 more sources

Analysis and construction of a family of refinable functions based on generalized Bernstein polynomials

Journal of Inequalities and Applications, 2016
In this paper, we construct a new family of refinable functions from generalized Bernstein polynomials, which include pseudo-splines of Type II. A comprehensive analysis of the refinable functions is carried out.
Ting Cheng, Xiaoyuan Yang
doaj   +1 more source

The nonlocal multipoint problem with Dirichlet-type conditions for an ordinary differential equation of even order with involution

Математичні Студії, 2020
The spectral properties of the nonself-adjoint problem with multipoint perturbations of the Dirichlet conditions for differential operator of order $2n$ with involution are investigated. The system of eigenfunctions of a multipoint problem is constructed.
Ya.O. Baranetskij, P.I. Kalenyuk, M. I. Kopach, A.V. Solomko   +3 more
doaj   +1 more source

Inverse problems of determining an unknown depending on time coefficient for a parabolic equation with involution and periodicity conditions

Karpatsʹkì Matematičnì Publìkacìï, 2023
The solution of the investigated problem with an unknown coefficient in the equation was constructed by using the method of separation of variables. The properties of the induced spectral problem for the second-order differential equation with involution
Ya.O. Baranetskij, I.I. Demkiv, A.V. Solomko   +2 more
doaj   +1 more source

Finite Element Approximation for a Reformulation of a 3D Fluid–2D Plate Interaction System

Numerical Methods for Partial Differential Equations, Volume 42, Issue 4, July 2026.
ABSTRACT We study a finite element approximation of a coupled fluid‐structure interaction consisting of a three‐dimensional incompressible viscous fluid governed by the unsteady Stokes equations and a two‐dimensional elastic plate. To avoid the use of H2−$$ {H}^2- $$conforming or nonconforming ℙ2$$ {\mathbb{P}}_2 $$‐Morley plate elements, the fourth ...
Lander Besabe, Hyesuk Lee
wiley   +1 more source

Operator Characterizations and Some Properties of g-Frames on Hilbert Spaces

Journal of Function Spaces and Applications, 2013
Given the g-orthonormal basis for Hilbert space H, we characterize the g-frames, normalized tight g-frames, and g-Riesz bases in terms of the g-preframe operators.
Xunxiang Guo
doaj   +1 more source

Riesz basis property of Hill operators with potentials in weighted spaces [PDF]

Transactions of the Moscow Mathematical Society, 2014
Consider the Hill operator $L(v) = - d^2/dx^2 + v(x) $ on $[0,π]$ with Dirichlet, periodic or antiperiodic boundary conditions; then for large enough $n$ close to $n^2 $ there are one Dirichlet eigenvalue $μ_n$ and two periodic (if $n$ is even) or antiperiodic (if $n$ is odd) eigenvalues $λ_n^-, \, λ_n^+ $ (counted with multiplicity).
Djakov, Plamen, Mityagin, Boris
openaire   +3 more sources

Advanced control of non‐isothermal axial dispersion tubular reactors with recycle‐induced state delay

The Canadian Journal of Chemical Engineering, Volume 104, Issue 6, Page 3018-3037, June 2026.
Abstract We develop a delay‐aware estimation and control framework for a non‐isothermal axial dispersion tubular reactor modelled as a coupled parabolic‐hyperbolic PDE system with recycle‐induced state delay. The infinite‐dimensional dynamics are preserved without spatial discretization by representing the delay as a transport PDE and adopting a late ...
Behrad Moadeli, Stevan Dubljevic
wiley   +1 more source