Results 71 to 80 of about 626,225 (308)
Some spectral properties of fourth order differential operator equation [PDF]
Operators and Matrices, 2018 Consider in the separable Hilbert space \(H\) the eigenvalue problem \[ \begin{gathered} y^{(4)}(x)+ Ay(x)+ q(x) y(x)= \lambda y(x),\qquad ...
Aslanova, Nigar M. +2 more
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Arthritis Care &Research, EarlyView.Objective Relapsing polychondritis (RP) is a rare disease defined by recurrent cartilaginous inflammation. Anti–collagen II (Col2) antibodies have been proposed as a diagnostic biomarker for RP, but their performance characteristics are not well defined.
Karyssa Stonick +6 more
wiley +1 more source
Oscillatory solutions of nonlinear fourth order differential equations with a middle term
Electronic Journal of Qualitative Theory of Differential Equations, 2014 We study the oscillation of a fourth order nonlinear differential equation with a middle term. Using a certain energy function, we describe the properties of oscillatory solutions.
Miroslav Bartusek, Zuzana Dosla
doaj +1 more source
Algebraic treatment of the Pais-Uhlenbeck oscillator and its PT-variant
, 2019 The algebraic method enables one to study the properties of the spectrum of a quadratic Hamiltonian through the mathematical properties of a matrix representation called regular or adjoint.
Fernández, Francisco M.
core +1 more source
Retractions in Rheumatology: Trends, Causes, and Implications for Research Integrity
Arthritis Care &Research, EarlyView.Objective We aimed to describe the trends and main reasons for study retraction in rheumatology literature. Methods We reviewed the Retraction Watch database to identify retracted articles in rheumatology. We recorded the main study characteristics, authors’ countries, reasons for retraction, time from publication to retraction, and trends over time ...
Anna Maria Vettori, Michele Iudici
wiley +1 more source
Semi-commuting and commuting operators for the Heun family
, 2017 We derive the most general families of differential operators of first and second degree semi-commuting with the differential operators of the Heun class. Among these families we classify all those families commuting with the Heun class.
Batic, Davide +2 more
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Infinitely many solutions for a fourth-order differential equation on a nonlinear elastic foundation
, 2013 In this paper, existence results of infinitely many solutions for a fourth-order differential equation with nonlinear boundary conditions are established. The proof is based on variational methods. Some recent results are improved and extended.
Xiaodan Wang
semanticscholar +1 more source
Correction to: “Periodic solutions of fourth-order differential equations” [PDF]
Proceedings of the American Mathematical Society, 1967 1. M. Abramowitz and I. A. Stegun, Handbook of mathematical functions with formulas, graphs, and mathematical tables, National Bureau of Standards, Applied Mathematics Series 55, 3rd printing, with corrections, March, 1965. 2. P. F. Hsieh and Y. Sibuya, On the asymptotic integration of second order linear ordinary differential equations with polynomial
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A Q‐Learning Algorithm to Solve the Two‐Player Zero‐Sum Game Problem for Nonlinear Systems
International Journal of Adaptive Control and Signal Processing, Volume 39, Issue 3, Page 566-581, March 2025.A Q‐learning algorithm to solve the two‐player zero‐sum game problem for nonlinear systems. ABSTRACT This paper deals with the two‐player zero‐sum game problem, which is a bounded L2$$ {L}_2 $$‐gain robust control problem. Finding an analytical solution to the complex Hamilton‐Jacobi‐Issacs (HJI) equation is a challenging task.
Afreen Islam +2 more
wiley +1 more source
Advanced Engineering Materials, Volume 27, Issue 6, March 2025.The stability criteria affecting the formation of high‐entropy alloys, particularly focusing in supersaturated solid solutions produced by mechanical alloying, are analyzed. Criteria based on Hume–Rothery rules are distinguished from those derived from thermodynamic relations. The formers are generally applicable to mechanically alloyed samples.
Javier S. Blázquez +5 more
wiley +1 more source