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Hénon Map


The name Hénon map refers to at least two maps.

The first is the two-dimensional dissipative quadratic map given by the coupled equations

x_(n+1)=1-alphax_n^2+y_n
(1)
y_(n+1)=betax_n
(2)

(Hénon 1976).

HenonMap

The strange attractor illustrated above is obtained for alpha=1.4 and beta=0.3.

Writing the first map as F(x,y)=(1-alphax^2+y,betax), its Jacobian matrix and Jacobian determinant are

J_F(x,y)=[-2alphax 1; beta 0]
(3)
detJ_F(x,y)=-beta.
(4)

It is therefore invertible when beta!=0, with

 F^(-1)(x,y)=(y/beta,x-1+(alphay^2)/(beta^2)).
(5)

The map scales signed area by -beta and area by |beta| at every iteration (Liang 2016). Consequently, whenever its two Lyapunov characteristic exponents exist, their sum is given by

 lambda_1+lambda_2=ln|beta|
(6)

(Eckmann and Ruelle 1985). In particular, the standard value beta=0.3 makes the map area-contracting.

HenonMapEscape

The illustration above shows two regions of space for the map with alpha=0.2 and beta=1.01 colored according to the number of iterations required to escape (Michelitsch and Rössler 1989).

HenonMaps

The plots above show evolution of the point (0,0) for parameters (alpha,beta)=(0.2,0.9991) (left) and (0.2,-0.9999) (right).

The Hénon map has correlation exponent 1.25+/-0.02 (Grassberger and Procaccia 1983) and capacity dimension 1.261+/-0.003 (Russell et al. 1980). Hitzl and Zele (1985) give conditions for the existence of periods 1 to 6.

Trott (2006) uses the normalization

 H(X,Y)=(a-X^2+bY,X).
(7)

For alphabeta!=0, the linear coordinate transformation X=alphax, Y=alphay/beta converts the first map to this form with a=alpha and b=beta. For real a and b, its fixed points are (u,u), where

 u^2+(1-b)u-a=0.
(8)

A real fixed point therefore exists iff (1-b)^2+4a>=0.

A point p has least period 3 under H iff

 H^3(p)=p ^ H(p)!=p,
(9)

where H^3 denotes the third iteration. The equation H^3(p)=p alone also admits fixed points. Eliminating the coordinates of a real point p by quantifier elimination gives conditions on the parameters a and b. For example, a=2 and b=-1 give the orbit

 (0,1)->(1,0)->(1,1)->(0,1),
(10)

whose three distinct points have least period 3. Endler and Gallas (2002) give a polynomial of polynomial degree 4 that parametrizes orbits of least period 4.

A second Hénon map is the quadratic area-preserving map

x_(n+1)=x_ncosalpha-(y_n-x_n^2)sinalpha
(11)
y_(n+1)=x_nsinalpha+(y_n-x_n^2)cosalpha
(12)

(Hénon 1969), which is one of the simplest two-dimensional invertible maps.


See also

Bogdanov Map, Gingerbreadman Map, Lozi Map, Quadratic Map, Signed Area

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References

Dickau, R. M. "The Hénon Attractor." https://www.robertdickau.com/henon.html.Eckmann, J.-P. and Ruelle, D. "Ergodic Theory of Chaos and Strange Attractors." Rev. Mod. Phys. 57, 617-656, 1985. https://doi.org/10.1103/RevModPhys.57.617.Endler, A. and Gallas, J. A. C. "Arithmetical Signatures of the Dynamics of the Hénon Map." Phys. Rev. E 65, 036231, 2002. https://doi.org/10.1103/PhysRevE.65.036231.Gleick, J. Chaos: Making a New Science. New York: Penguin Books, pp. 144-153, 1988.Grassberger, P. and Procaccia, I. "Measuring the Strangeness of Strange Attractors." Physica D 9, 189-208, 1983.Hénon, M. "Numerical Study of Quadratic Area-Preserving Mappings." Quart. Appl. Math. 27, 291-312, 1969.Hénon, M. "A Two-Dimensional Mapping with a Strange Attractor." Comm. Math. Phys. 50, 69-77, 1976.Hitzl, D. H. and Zele, F. "An Exploration of the Hénon Quadratic Map." Physica D 14, 305-326, 1985.Lauwerier, H. Fractals: Endlessly Repeated Geometric Figures. Princeton, NJ: Princeton University Press, pp. 128-133, 1991.Liang, X. S. "Information Flow and Causality as Rigorous Notions Ab Initio." Phys. Rev. E 94, 052201, 2016. https://doi.org/10.1103/PhysRevE.94.052201.Michelitsch, M. and Rössler, O. E. "A New Feature in Hénon's Map." Comput. & Graphics 13, 263-275, 1989. Reprinted in Chaos and Fractals, A Computer Graphical Journey: Ten Year Compilation of Advanced Research (Ed. C. A. Pickover). Amsterdam, Netherlands: Elsevier, pp. 69-71, 1998.Morosawa, S.; Nishimura, Y.; Taniguchi, M.; and Ueda, T. "Dynamics of Generalized Hénon Maps." Ch. 7 in Holomorphic Dynamics. Cambridge, England: Cambridge University Press, pp. 225-262, 2000.Peitgen, H.-O. and Richter, D. H. The Beauty of Fractals: Images of Complex Dynamical Systems. New York: Springer-Verlag, 1986.Peitgen, H.-O. and Saupe, D. (Eds.). "A Chaotic Set in the Plane." §3.2.2 in The Science of Fractal Images. New York: Springer-Verlag, pp. 146-148, 1988.Russell, D. A.; Hanson, J. D.; and Ott, E. "Dimension of Strange Attractors." Phys. Rev. Let. 45, 1175-1178, 1980.Trott, M. "Polynomials in Inequalities." §1.2.3 in The Mathematica GuideBook for Symbolics. New York: Springer-Verlag, 2006. https://doi.org/10.1007/0-387-28815-5. https://www.mathematicaguidebooks.org/.Wells, D. The Penguin Dictionary of Curious and Interesting Geometry. London, England: Penguin, pp. 95-97, 1991.

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Hénon Map

Cite this as:

Weisstein, Eric W. "Hénon Map." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/HenonMap.html

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