Results 1 to 10 of about 26,513 (266)

Charged Shear-Free Fluids and Complexity in First Integrals [PDF]

Entropy, 2022
The equation yxx=f(x)y2+g(x)y3 is the charged generalization of the Emden-Fowler equation that is crucial in the study of spherically symmetric shear-free spacetimes.
Sfundo C. Gumede, Keshlan S. Govinder, Sunil D. Maharaj   +2 more
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First Integrals of Shear-Free Fluids and Complexity [PDF]

Entropy, 2021
A single master equation governs the behaviour of shear-free neutral perfect fluid distributions arising in gravity theories. In this paper, we study the integrability of yxx=f(x)y2, find new solutions, and generate a new first integral.
Sfundo C. Gumede, Keshlan S. Govinder, Sunil D. Maharaj   +2 more
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Solutions for Multitime Reaction–Diffusion PDE

Mathematics, 2022
A previous paper by our research group introduced the nonlinear multitime reaction–diffusion PDE (with oblique derivative) as a generalized version of the single-time model.
Cristian Ghiu, Constantin Udriste
doaj   +1 more source

Integrability and Limit Cycles via First Integrals [PDF]

Symmetry, 2021
In many problems appearing in applied mathematics in the nonlinear ordinary differential systems, as in physics, chemist, economics, etc., if we have a differential system on a manifold of dimension, two of them having a first integral, then its phase portrait is completely determined.
openaire   +2 more sources

Invariant Algebraic Curves of Generalized Liénard Polynomial Differential Systems

Mathematics, 2022
In this study, we focus on invariant algebraic curves of generalized Liénard polynomial differential systems x′=y, y′=−fm(x)y−gn(x), where the degrees of the polynomials f and g are m and n, respectively, and we correct some results previously stated.
Jaume Giné, Jaume Llibre
doaj   +1 more source

Godunova Type Inequality for Sugeno Integral [PDF]

Sahand Communications in Mathematical Analysis, 2022
In this paper, we investigate  Godunova type inequality for Sugeno integrals in two cases. At the first case, we suppose that the inner integral is the  Riemann integral and the remaining two integrals are of Sugeno type.
Bayaz Daraby, Alireza Khodadadi, Asghar Rahimi   +2 more
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Covariants, Invariant Subsets, and First Integrals [PDF]

Épijournal de Géométrie Algébrique, 2020
Let $k$ be an algebraically closed field of characteristic 0, and let $V$ be a finite-dimensional vector space. Let $End(V)$ be the semigroup of all polynomial endomorphisms of $V$.
Frank Grosshans, Hanspeter Kraft
doaj   +1 more source

The Routh theorem for mechanical systems with unknown first integrals [PDF]

Theoretical and Applied Mechanics, 2017
In this paper we discuss problems of stability of stationary motions of conservative and dissipative mechanical systems with first integrals. General results are illustrated by the problem of motion of a rotationally symmetric rigid body on a perfectly ...
Karapetyan Alexander V., Kuleshov Alexander S.   +1 more
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Darboux and rational first integrals for a family of cubic three dimensional systems

Zanco Journal of Pure and Applied Sciences, 2021
In this paper, we investigate the first integrals of the following system exam.PNG exam1.PNG This kind of system is a particular case of the jerk cubic three dimensional polynomial differential systems.
Sarbast Hussein Mikaeel, Azad I. Amen
doaj   +1 more source

Exact solutions, Lagrangians and first integrals for generalized Camassa–Holm equation

Partial Differential Equations in Applied Mathematics, 2021
In this paper, Lagrangians and the first integrals of a new class of Liénard-type equations have been investigated. This class can be obtained using the traveling wave reduction of the generalized Camassa–Holm equation.
H. Elzehri, A.H. Abdel Kader, M.S. Abdel Latif   +2 more
doaj   +1 more source