Results 151 to 160 of about 5,511,845 (178)

A class of non-integrable systems admitting an inverse integrating factor

Journal of Mathematical Analysis and Applications, 2014
We study the existence of an inverse integrating factor for a class of systems, in general non-integrable, whose lowest-degree quasi-homogeneous term is a Hamiltonian system and its Hamiltonian function only has simple factors over C[x; y].
Antonio Algaba, Cristobal García García, M Reyes   +2 more
exaly   +4 more sources

Polynomial inverse integrating factors for polynomial vector fields

Discrete and Continuous Dynamical Systems, 2007
We present some results and one open question on the existence of polynomial inverse integrating factors for polynomial vector fields.
Adam Mahdi, Antoni Ferragut, Jaume Llibre   +2 more
exaly   +2 more sources

PHASE PORTRAITS OF THE QUADRATIC SYSTEMS WITH A POLYNOMIAL INVERSE INTEGRATING FACTOR

International Journal of Bifurcation and Chaos in Applied Sciences and Engineering, 2009
We classify the phase portraits of all planar quadratic polynomial differential systems having a polynomial inverse integrating factor.
Antoni Ferragut, Jaume Llibre
exaly   +4 more sources

Polynomial inverse integrating factors for quadratic differential systems

Nonlinear Analysis: Theory, Methods & Applications, 2010
The authors consider the real planar quadratic polynomial system \[ \dot x = P(x,y), \quad \dot y = Q(x,y), \tag{1} \] where the dot denotes the derivative with respect to the time variable, and \(P,Q\) are quadratic polynomials. A function \(R(x,y)\) is called integrating factor of system (1), if \(R\) is a solution of the equation \(\text{div}(RP,RQ)
Coll, Bartomeu, Ferragut, Antoni, Llibre, Jaume   +2 more
openaire   +2 more sources

Photon output factor calculation from the inverse of the sector-integration equation

Medical Physics, 1999
A method to predict rectangular field output factors (OFs) of photon open beams for the Saturne 41 linear accelerator has been developed. The procedure is similar to the sector-integration method but the radiotherapy quantities corresponding to circular fields (circular functions) are calculated from one-dimensional OFs.
D E, Sanz, A L, Romaguera, N B, Acosta
openaire   +2 more sources

Existence and nonexistence of Puiseux inverse integrating factors in analytic monodromic singularities

Studies in Applied Mathematics
AbstractIn this work, we present some criteria about the existence and nonexistence of both Puiseux inverse integrating factors and Puiseux first integrals for planar analytic vector fields having a monodromic singularity. These functions are a wide generalization of their formal or algebraic counterpart in Cartesian coordinates . We prove that none
Isaac A Garcia, Jaume Giné, Ana Livia Rodero   +2 more
exaly   +3 more sources

Integrability of the 2D Lotka-Volterra system via polynomial first integrals and polynomial inverse integrating factors

Journal of Physics A: Mathematical and General, 2000
The authors show new first integrals to planar Lotka-Volterra systems that have a polynomial inverse integrating factor. These systems may be characterized by equalities among the coefficients of the system. Moreover, all planar Lotka-Volterra systems which have a polynomial first integral are characterized and an explicit expression of these first ...
Cairó, Laurent, Llibre, Jaume
openaire   +1 more source

Existence and vanishing set of inverse integrating factors for analytic vector fields

Bulletin of the London Mathematical Society, 2009
In this paper we address the problem of existence of inverse integrating factors for an analytic planar vector field in a neighborhood of its nonwandering sets. It is proved that there always exists a smooth inverse integrating factor in a neighborhood of a limit cycle, obtaining a necessary and sufficient condition for the existence of an analytic one.
Alberto Enciso, Daniel Peralta-Salas
openaire   +1 more source

Algebraic Inverse Integrating Factors for a Class of Generalized Nilpotent Systems

2016
Usually, the study of differential systems with linear part null is done using quasi-homogeneous expansions of vector fields. Here, we use this technique for analyzing the existence of an inverse integrating factor for generalized nilpotent systems, in general non-integrable, whose lowest-degree quasi-homogeneous term is the Hamiltonian system \(y^{2 ...
Antonio Algaba, Natalia Fuentes, Cristóbal García, Manuel Reyes   +3 more
openaire   +1 more source

Inverse integrating factor overview

AIP Conference Proceedings, 2023
Anmar Hashim Jasim, Zainab Mohammed Alwan   +1 more
openaire   +1 more source