Investigation of center manifolds of three-dimensional systems using computer algebra

2013 ◽  
Vol 39 (2) ◽  
pp. 67-73 ◽  
Author(s):  
V. G. Romanovski ◽  
M. Mencinger ◽  
B. Ferčec
2021 ◽  
Vol 0 (0) ◽  
pp. 0
Author(s):  
Brigita Ferčec ◽  
Valery G. Romanovski ◽  
Yilei Tang ◽  
Ling Zhang

<p style='text-indent:20px;'>We study integrability and bifurcations of a three-dimensional circuit differential system. The emerging of periodic solutions under Hopf bifurcation and zero-Hopf bifurcation is investigated using the center manifolds and the averaging theory. The zero-Hopf equilibrium is non-isolated and lies on a line filled in with equilibria. A Lyapunov function is found and the global stability of the origin is proven in the case when it is a simple and locally asymptotically stable equilibrium. We also study the integrability of the model and the foliations of the phase space by invariant surfaces. It is shown that in an invariant foliation at most two limit cycles can bifurcate from a weak focus.</p>


2018 ◽  
pp. 51-58

Un modelo para visualizar objetos en 4D con el Mathematica A model to visualize objects in 4D with Mathematica Ricardo Velezmoro y Robert Ipanaqué Universidad Nacional de Piura, Urb. Miraflores s/n, Castilla, Piura, Perú.  DOI: https://doi.org/10.33017/RevECIPeru2014.0008/ Resumen Una variedad de técnicas de gráficos por computadora han permitido la visualización de objetos, que existen en dimensiones más altas, en una pantalla 2D. En este artículo se propone un nuevo modelo a partir de la extensión de una técnica útil en la visualización de objetos en 3D en una pantalla 2D para realizar algo similar con objetos en 4D. Dicha técnica se basa en la definición de una inmersión, en primera instancia, del espacio tridimensional en el espacio bidimensional que luego se toma como referencia para definir otra inmersión, que constituye el modelo propuesto en este artículo, del espacio tetra dimensional en el espacio tridimensional. En teoría la visualización de objetos en 4D en una pantalla 2D se consigue mediante la composición de las dos inmersiones mencionadas, pero en la práctica se aprovechan los comandos incorporados en el sistema de cálculo simbólico Mathematica para tal fin. Descriptores: objetos 4D, modelo, inmersión Abstract A variety of computer graphics techniques have enabled the display of objects, which exist in higher dimensions, on a 2D screen. In this paper a new model from the extension of a technique useful in visualizing 3D objects on a 2D screen to make something similar with 4D objects is proposed. This technique is based on the definition of a immersion, in the first instance, from the three-dimensional space in two-dimensional space which is then taken as a reference to define another immersion, which is the model proposed in this paper, from the fourdimensional space in three dimensional space. Theoretically the visualization of objects in 4D on a 2D screen is achieved by the composition of the two immersions mentioned, but in practice the incorporated commands into the computer algebra system Mathematica for this purpose are utilized. Keywords: objects 4D, model, immersion.


Filomat ◽  
2009 ◽  
Vol 23 (2) ◽  
pp. 68-81
Author(s):  
Predrag Stanimirovic ◽  
Marko Petkovic ◽  
Milan Zlatanovic

We show how the computer algebra system in MATHEMATICA and its graphical capabilities can be used in optimization. A package for teaching the graphical solution of two-dimensional and three-dimensional linear programming problem is developed.


Author(s):  
A. D. Blackowiak ◽  
R. H. Rand ◽  
H. Kaplan

Abstract Starting with a no-slip, dissipation-free model of the celt developed by Kane and Levinson in 1982, we obtain a three-dimensional slow flow using second order averaging. The coefficients of the slow flow are obtained in symbolic form through the use of computer algebra, thus permitting a bifurcation analysis to be performed. It is shown that for all physically relevant parameters the celt is predicted to exhibit an infinite number of spin reversals. The analysis assumes small energy and small inertial asymmetry.


1998 ◽  
Vol 09 (03) ◽  
pp. 509-525 ◽  
Author(s):  
Richard J. Fateman

Using a classic example proposed by G. I. Taylor, we reconsider through the use of computer algebra, the mathematical analysis of a fundamental process in turbulent flow, namely: How do large scale eddies evolve into smaller scale ones to the point where they are effectively absorbed by viscosity? The explicit symbolic series solution of this problem, even for cleverly chosen special cases, requires daunting algebra, and so numerical methods have become quite popular. Yet an algebraic approach can provide substantial insight, especially if it can be pursued with modest human effort. The specific example we use dates to 1937 when Taylor and Green8 first published a method for explicitly computing successive approximations to formulas describing the three-dimensional evolution over time of what is now called a Taylor–Green vortex. With the aid of a computer algebra system, we have duplicated Taylor and Green's efforts and obtained more detailed time-series results. We have extended their approximation of the energy dissipation from order 5 in time to order 14, including the variation with viscosity. Rather than attempting additional interpretation of results for fluid flow (for which, see papers by Brachet et al.,2,3 we examine the promise of computer algebra in pursuing such problems in fluid mechanics.


1966 ◽  
Vol 25 ◽  
pp. 227-229 ◽  
Author(s):  
D. Brouwer

The paper presents a summary of the results obtained by C. J. Cohen and E. C. Hubbard, who established by numerical integration that a resonance relation exists between the orbits of Neptune and Pluto. The problem may be explored further by approximating the motion of Pluto by that of a particle with negligible mass in the three-dimensional (circular) restricted problem. The mass of Pluto and the eccentricity of Neptune's orbit are ignored in this approximation. Significant features of the problem appear to be the presence of two critical arguments and the possibility that the orbit may be related to a periodic orbit of the third kind.


Author(s):  
M. Boublik ◽  
W. Hellmann ◽  
F. Jenkins

The present knowledge of the three-dimensional structure of ribosomes is far too limited to enable a complete understanding of the various roles which ribosomes play in protein biosynthesis. The spatial arrangement of proteins and ribonuclec acids in ribosomes can be analysed in many ways. Determination of binding sites for individual proteins on ribonuclec acid and locations of the mutual positions of proteins on the ribosome using labeling with fluorescent dyes, cross-linking reagents, neutron-diffraction or antibodies against ribosomal proteins seem to be most successful approaches. Structure and function of ribosomes can be correlated be depleting the complete ribosomes of some proteins to the functionally inactive core and by subsequent partial reconstitution in order to regain active ribosomal particles.


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