Results 11 to 20 of about 4,114,452 (292)

Gravitational lensing in fourth order gravity [PDF]

, 2006
Gravitational lensing is investigated in the weak field limit of fourth order gravity in which the Lagrangian of the gravitational field is modified by replacing the Ricci scalar curvature R with an analytical expression $f(R)$. Considering the case of a
A. Troisi, A. O. Petters, I. Quandt, P. Schneider, Ph. Jetzer, S. Capozziello, S. Mollerach, V. F. Cardone, V. Faraoni   +8 more
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Second order splitting of a class of fourth order PDEs with point constraints [PDF]

, 2020
We formulate a well-posedness and approximation theory for a class of generalised saddle point problems with a specific form of constraints. In this way we develop an approach to a class of fourth order elliptic partial differential equations with point ...
Elliott, Charles M., Herbert, P. J.
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On a fourth order nonlinear Helmholtz equation [PDF]

, 2018
In this paper, we study the mixed dispersion fourth order nonlinear Helmholtz equation $\Delta^2 u -\beta \Delta u + \alpha u= \Gamma|u|^{p-2} u$ in $\mathbb R^N$ for positive, bounded and $\mathbb Z^N$-periodic functions $\Gamma$.
Abramowitz M., Bonheure D., Bonheure D., Denis Bonheure, Evéquoz G., Gilbarg D., Jean‐Baptiste Casteras, Lorenzi L., Rainer Mandel, Stein E. M., Stein E. M., Sulem C.   +11 more
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Oscillation theorems for fourth-order quasi-linear delay differential equations

AIMS Mathematics, 2023
In this paper, we deal with the asymptotic and oscillatory behavior of quasi-linear delay differential equations of fourth order. We first find new properties for a class of positive solutions of the studied equation, $ \mathcal{N}_{a} $.
Fahd Masood , Osama Moaaz, Shyam Sundar Santra, U. Fernandez-Gamiz, Hamdy A. El-Metwally   +4 more
doaj   +1 more source

Single-shot fourth-order autocorrelator [PDF]

Advanced Photonics, 2019
The temporal contrast is one of the most important parameters of an ultra-high intense laser pulse. Third-order auto-correlator or cross-correlator have been widely used to characterize the temporal contrast of an ultra-intense laser pulse in the past decades.
Wang, Peng, Shen, Xiong, Liu, Jun, Li, Ruxin   +3 more
openaire   +2 more sources

Fourth-order explicit hybrid method for solving special second-order ordinary differential equations [PDF]

, 2012
In this paper, a fourth-order explicit hybrid method with constant step-size is developed. The free parameters are chosen so that the error constant is small.
Ismail, Fudziah, Samat, Faieza
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Fourth-Order Neutral Differential Equation: A Modified Approach to Optimizing Monotonic Properties

Mathematics, 2023
In this article, we investigate some qualitative properties of solutions to a class of functional differential equations with multi-delay. Using a modified approach, we first derive a number of optimized relations and inequalities that relate the ...
Amany Nabih, Osama Moaaz, Sameh S. Askar, Ahmad M. Alshamrani, Elmetwally M. Elabbasy   +4 more
doaj   +1 more source

On fourth-order jacobsthal quaternions

Journal of Mathematical Sciences and Modelling, 2018
In this paper, we present for the first time a sequence of quaternions of order 4 that we will call the fourth-order Jacobsthal and the fourth-order Jacobsthal-Lucas quaternions. In particular, we are interested in the generating function, Binet formula,
Gamaliel Cerda-morales
doaj   +1 more source

Numerical Analysis of Transmission Lines Equation by new β-method Schemes

Analele Stiintifice ale Universitatii Ovidius Constanta: Seria Matematica, 2017
In this paper we develop a new β-method applied to the resolution of homogeneous transmission lines. A comparison with conventional methods used for this type of problems like FDTD method or classical β-method is also given.
Allali Fatima, Alaa Nour Eddine, Ghammaz Abdelilah, Rouijaa Hicham   +3 more
doaj   +1 more source

Higher-Order Singular BVP Emerging in the Semiconductor Industry: Analysis and Computation of Solutions [PDF]

Journal of Applied and Computational Mechanics
In this work, we consider a class of non-linear, singular, non-self-adjoint, fourth-order, and singular BVP arising in the semiconductor industry. We investigate the theoretical and numerical results of solutions for the governing model corresponding to ...
Pratikshya Mainini, Biswajit Pandit, B.R. Priyanka, Ravi Agarwal   +3 more
doaj   +1 more source