Results 11 to 20 of about 395,045 (283)

A Survey on the Inverse Integrating Factor [PDF]

Qualitative Theory of Dynamical Systems, 2010
The relation between limit cycles of planar differential systems and the inverse integrating factor was first shown in an article of Giacomini, Llibre and Viano appeared in 1996. From that moment on, many research articles are devoted to the study of the properties of the inverse integrating factor and its relation with limit cycles and their ...
García, Isaac A., Grau, Maite
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On the Integrability of Quasihomogeneous Systems and Quasidegenerate Infinity Systems

Advances in Difference Equations, 2007
The integrability of quasihomogeneous systems is considered, and the properties of the first integrals and the inverse integrating factors of such systems are shown.
Hu Yanxia
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The inverse integrating factor and the Poincaré map [PDF]

Transactions of the American Mathematical Society, 2010
27 pages, no ...
García, Isaac A., Giacomini, Héctor, Grau, Maite   +2 more
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Mendelian Randomization With Refined Instrumental Variables From Genetic Score Improves Accuracy and Reduces Bias

Frontiers in Genetics, 2021
Mendelian randomization (MR) can estimate the causal effect for a risk factor on a complex disease using genetic variants as instrument variables (IVs). A variety of generalized MR methods have been proposed to integrate results arising from multiple IVs
Lijuan Lin, Ruyang Zhang, Ruyang Zhang, Ruyang Zhang, Ruyang Zhang, Hui Huang, Ying Zhu, Yi Li, Xuesi Dong, Xuesi Dong, Sipeng Shen, Liangmin Wei, Xin Chen, David C. Christiani, David C. Christiani, David C. Christiani, Yongyue Wei, Yongyue Wei, Yongyue Wei, Yongyue Wei, Feng Chen, Feng Chen, Feng Chen, Feng Chen   +23 more
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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, García, Cristóbal, Giné, Jaume   +2 more
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Obesity as a Condition Determined by Food Addiction: Should Brain Endocannabinoid System Alterations Be the Cause and Its Modulation the Solution?

Pharmaceuticals, 2021
Obesity is a complex disorder, and the number of people affected is growing every day. In recent years, research has confirmed the hypothesis that food addiction is a determining factor in obesity. Food addiction is a behavioral disorder characterized by
Marialuisa de Ceglia, Juan Decara, Silvana Gaetani, Fernando Rodríguez de Fonseca   +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, Llibre, Jaume, Pantazi, Chara, Walcher, Sebastian   +3 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, Giacomini, Hector, Giné, Jaume, Llibre, Jaume   +3 more
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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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Realization problems for limit cycles of planar polynomial vector fields [PDF]

, 2015
We show that for any finite configuration of closed curves $\Gamma\subset \mathbb{R}^2$, one can construct an explicit planar polynomial vector field that realizes $\Gamma$, up to homeomorphism, as the set of its limit cycles with prescribed periods ...
Margalef-Bentabol, Juan, Peralta-Salas, Daniel   +1 more
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