Results 21 to 30 of about 55,893 (253)
Nilpotent centres via inverse integrating factors [PDF]
European Journal of Applied Mathematics, 2016 In this paper, we are interested in the nilpotent centre problem of planar analytic monodromic vector fields. It is known that the formal integrability is not enough to characterize such centres. More general objects are considered as the formal inverse integrating factors. However, the existence of a formal inverse integrating factor is not sufficient
Algaba, Antonio +2 more
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Darboux integrability and the inverse integrating factor
Journal of Differential Equations, 2003 Consider planar (real or complex) polynomial vector fields \(X=P(x,y)\partial_x+Q(x,y)\partial_y\) having a Darboux first integral of the form \[ H= f_1^{\lambda_1}\cdots f_p^{\lambda_p} \left( \exp\left( {h_1}\over {g_1} \right) \right)^{\mu_1} \cdots \left( \exp\left({h_q}\over{g_q} \right) \right)^{\mu_q}, \] where \(f_i, g_i\) and \(h_i\) are ...
Chavarriga, Javier +3 more
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Darboux integrating factors: Inverse problems
Journal of Differential Equations, 2011 We discuss planar polynomial vector fields with prescribed Darboux integrating factors, in a nondegenerate affine geometric setting. We establish a reduction principle which transfers the problem to polynomial solutions of certain meromorphic linear systems, and show that the space of vector fields with a given integrating factor, modulo a subspace of ...
Christopher, Colin +3 more
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Formal Inverse Integrating Factor and the Nilpotent Center Problem [PDF]
International Journal of Bifurcation and Chaos, 2016 We are interested in deepening the knowledge of methods based on formal power series applied to the nilpotent center problem of planar local analytic monodromic vector fields [Formula: see text]. As formal integrability is not enough to characterize such a center we use a more general object, namely, formal inverse integrating factors [Formula: see ...
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Integrable systems via polynomial inverse integrating factors
Bulletin des Sciences Mathématiques, 2002 The authors study the center problem for planar ordinary differential equations of the form \[ x'=-y+X_s(x,y),\qquad y'=x+Y_s(x,y), \] where \(X_s\) and \(Y_s\) are homogeneous polynomials of degree \(s.\) These systems write in polar coordinates as \(r'=P_s(\varphi)r^s,\) \(\varphi'=1+Q_s(\varphi)r^{s-1}\), where \[ \begin{aligned} P_s(\varphi)&= R_{s+
Chavarriga, J., Giné, J., Grau, M.
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On the Shape of Limit Cycles That Bifurcate from Isochronous Center
The Scientific World Journal, 2014 New idea and algorithm are proposed to compute asymptotic expression of limit cycles bifurcated from the isochronous center. Compared with known inverse integrating factor method, new algorithm to analytically computing shape of limit cycle proposed in ...
Guang Chen, Yuhai Wu
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Scattering and absorption properties of biomaterials for dental restorative applications [PDF]
Journal of the European Optical Society-Rapid Publications, 2013 The physical understanding of the optical properties of dental biomaterials is mandatory for their final success in restorative applications. Light propagation in biological media is characterized by the absorption coefficient, the scattering coefficient,
Fernández-Oliveras A. +2 more
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Secondary Data Analytics of Aquaporin Expression Levels in Glioblastoma Stem-Like Cells
Cancer Informatics, 2015 Glioblastoma is the most common brain tumor in adults in which recurrence has been attributed to the presence of cancer stem cells in a hypoxic microenvironment.
Raphael D. Isokpehi +6 more
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Applied Sciences, 2019 With the developing of high integrations in large scale systems, such as aircraft and other industrial systems, there are new challenges in safety analysis due to the complexity of the mission process and the more complicated coupling characteristic of ...
Jian Jiao +3 more
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Molecular Brain, 2023 Background Stroke is a common cerebrovascular disease with great danger to public health. Educational inequality is a universal issue that influences populations’ stroke risk.
Bangbei Wan +3 more
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