Conditions for maximal regularity of solutions to fourth-order differential equations

This article investigates a fourth-order differential equation defined in a Hilbert space, with an unbounded intermediate coefficient and potential. The key distinction from previous research lies in the fact that the intermediate term of the equation does not obey to the differential operator form...

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Main Authors: Ye.O. Moldagali, K.N. Ospanov
Format: Article
Language:English
Published: Academician Ye.A. Buketov Karaganda University 2024-12-01
Series:Қарағанды университетінің хабаршысы. Математика сериясы
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Online Access:https://mathematics-vestnik.ksu.kz/index.php/mathematics-vestnik/article/view/630
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author Ye.O. Moldagali
K.N. Ospanov
author_facet Ye.O. Moldagali
K.N. Ospanov
author_sort Ye.O. Moldagali
collection DOAJ
description This article investigates a fourth-order differential equation defined in a Hilbert space, with an unbounded intermediate coefficient and potential. The key distinction from previous research lies in the fact that the intermediate term of the equation does not obey to the differential operator formed by its extreme terms. The study establishes that the generalized solution to the equation is maximally regular, if the intermediate coefficient satisfies an additional condition of slow oscillation. A corresponding coercive estimate is obtained, with the constant explicitly expressed in terms of the coefficients’ conditions. Fourth-order differential equations appear in various models describing transverse vibrations of homogeneous beams or plates, viscous flows, bending waves, and etc. Boundary value problems for such equations have been addressed in numerous works, and the results obtained have been extended to cases with smooth variable coefficients. The smoothness conditions imposed on the coefficients in this study are necessary for the existence of the adjoint operator. One notable feature of the results is that the constraints only apply to the coefficients themselves; no conditions are placed on their derivatives. Secondly, the coefficient of the lowest order in the equation may be zero, moreover, it may not be unbounded from below.
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institution Kabale University
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language English
publishDate 2024-12-01
publisher Academician Ye.A. Buketov Karaganda University
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series Қарағанды университетінің хабаршысы. Математика сериясы
spelling doaj-art-7b2d047ee25e4f93a614d5eeb4b0e31a2024-12-30T08:04:49ZengAcademician Ye.A. Buketov Karaganda UniversityҚарағанды университетінің хабаршысы. Математика сериясы2518-79292663-50112024-12-01116410.31489/2024m4/149-158Conditions for maximal regularity of solutions to fourth-order differential equationsYe.O. Moldagali0K.N. Ospanov1https://orcid.org/0000-0002-5480-2178L.N. Gumilyov Eurasian National University, Astana, KazakhstanL.N. Gumilyov Eurasian National University, Astana, Kazakhstan This article investigates a fourth-order differential equation defined in a Hilbert space, with an unbounded intermediate coefficient and potential. The key distinction from previous research lies in the fact that the intermediate term of the equation does not obey to the differential operator formed by its extreme terms. The study establishes that the generalized solution to the equation is maximally regular, if the intermediate coefficient satisfies an additional condition of slow oscillation. A corresponding coercive estimate is obtained, with the constant explicitly expressed in terms of the coefficients’ conditions. Fourth-order differential equations appear in various models describing transverse vibrations of homogeneous beams or plates, viscous flows, bending waves, and etc. Boundary value problems for such equations have been addressed in numerous works, and the results obtained have been extended to cases with smooth variable coefficients. The smoothness conditions imposed on the coefficients in this study are necessary for the existence of the adjoint operator. One notable feature of the results is that the constraints only apply to the coefficients themselves; no conditions are placed on their derivatives. Secondly, the coefficient of the lowest order in the equation may be zero, moreover, it may not be unbounded from below. https://mathematics-vestnik.ksu.kz/index.php/mathematics-vestnik/article/view/630fourth-order differential equationunbounded coefficientsolutionexistenceuniquenesssmoothness
spellingShingle Ye.O. Moldagali
K.N. Ospanov
Conditions for maximal regularity of solutions to fourth-order differential equations
Қарағанды университетінің хабаршысы. Математика сериясы
fourth-order differential equation
unbounded coefficient
solution
existence
uniqueness
smoothness
title Conditions for maximal regularity of solutions to fourth-order differential equations
title_full Conditions for maximal regularity of solutions to fourth-order differential equations
title_fullStr Conditions for maximal regularity of solutions to fourth-order differential equations
title_full_unstemmed Conditions for maximal regularity of solutions to fourth-order differential equations
title_short Conditions for maximal regularity of solutions to fourth-order differential equations
title_sort conditions for maximal regularity of solutions to fourth order differential equations
topic fourth-order differential equation
unbounded coefficient
solution
existence
uniqueness
smoothness
url https://mathematics-vestnik.ksu.kz/index.php/mathematics-vestnik/article/view/630
work_keys_str_mv AT yeomoldagali conditionsformaximalregularityofsolutionstofourthorderdifferentialequations
AT knospanov conditionsformaximalregularityofsolutionstofourthorderdifferentialequations