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1986 | Buch

The Beauty of Fractals

Images of Complex Dynamical Systems

verfasst von: Prof. Dr. Heinz-Otto Peitgen, Prof. Dr. Peter H. Richter

Verlag: Springer Berlin Heidelberg

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Über dieses Buch

In 1953 I realized that the straight line leads to the downfall of mankind. But the straight line has become an absolute tyranny. The straight line is something cowardly drawn with a rule, without thought or feeling; it is the line which does not exist in nature. And that line is the rotten foundation of our doomed civilization. Even if there are places where it is recognized that this line is rapidly leading to perdition, its course continues to be plot­ ted . . . Any design undertaken with the straight line will be stillborn. Today we are witnessing the triumph of rationalist knowhow and yet, at the same time, we find ourselves confronted with emptiness. An esthetic void, des­ ert of uniformity, criminal sterility, loss of creative power. Even creativity is prefabricated. We have become impotent. We are no longer able to create. That is our real illiteracy. Friedensreich Hundertwasser Fractals are all around us, in the shape of a mountain range or in the windings of a coast line. Like cloud formations and flickering fires some fractals under­ go never-ending changes while others, like trees or our own vascular systems, retain the structure they acquired in their development. To non-scientists it may seem odd that such familiar things have recently become the focus of in­ tense research. But familiarity is not enough to ensure that scientists have the tools for an adequate understanding.

Inhaltsverzeichnis

Frontmatter

Frontiers of chaos

Frontmatter

Special Sections

1. Verhulst Dynamics
Abstract
Let xo be the initial population size and x n its value after n years. The growth rate R is the relative increase per year.
$$R = \left( {x_{n + 1} - x_n } \right)/x_n .$$
Heinz-Otto Peitgen, Peter H. Richter
2. Julia Sets and their Computergraphical Generation
Abstract
This is a collection of some fundamental classical results from the work of Gaston Julia (1893–1978) and Pierre Fatou (1878–1929). For a more detailed review we recommend [Bl].
Heinz-Otto Peitgen, Peter H. Richter
3. Sullivan’s Classification and Critical Points
Abstract
From the complexity of the computer experimental results it may appear impossible to understand the global dynamics of a given rational map R. But Julia and Fatou already knew that many of its qualitative aspects are intimately linked to the dynamics of the critical points of R.
Heinz-Otto Peitgen, Peter H. Richter
4. The Mandelbrot Set
Abstract
For polynomials of second order, p(x) = a2x2 + a1x + ao, an almost complete classification of the corresponding Julia sets can be given in terms of the Mandelbrot set. First note that p(x is conjugate to p c (z)=z2 + c by means of the coordinate transformation \( x \mapsto z = a_2 x + a_1 /2,with{\text{ }}c = a_0 a_2 + \frac{{a_1 }} {2}\left( {1 - \frac{{a_1 }} {2}} \right). \)
Heinz-Otto Peitgen, Peter H. Richter
5. External Angles and Hubbard Trees
Abstract
It is well known that analytic functions f:ℂ→ℂ are a powerful tool for solving problems of two-dimensional electrostatics. The Cauchy-Riemann differential equations imply that Ref and Imf are both solutions to Laplace’s equation ∇2F= 0, and that the two families of curves Ref= const and Imf= const intersect each other orthogonally. Therefore, if u=Ref say, describes the surface of a charged conductor, the lines Ref= const are equipotential lines and Imf= const the corresponding field lines.
Heinz-Otto Peitgen, Peter H. Richter
6. Newton’s Method for Complex Polynomials: Cayley’s Problem
Abstract
Newton’s method and its sophisticated variants are among the most prominent numerical methods for finding solutions of nonlinear equations. The theory of these methods is usually presented in two parts, one with emphasis on the proof of convergence of the method, the other addressing the derivation of the asymptotic speed of convergence. The picture which one thus obtains from the literature is, however, somewhat incomplete. There are additional interesting and deep problems connected with Newton’s method one of which is the subject of the following discussion.
Heinz-Otto Peitgen, Peter H. Richter
7. Newton’s Method for Real Equations
Abstract
Much of the complexity which we have seen in Newton’s method for complex polynomials is known to be closely linked to the underlying complex analytic structure. Thus, it appears to be an interesting question to ask what the situation is like for systems of real equations. Note, however, that a complex analytic map ℂ∋x(x) can be regarded as a function of two real variables in a canonical way. viz. ƒ(x) — (ƒ1(x1, x2), ƒ2(x1, x2)) such that the Cauchy-Riemann differential equations are satisfied:
$$ |\frac{{\partial f_1 }} {{\partial x_1 }} = \frac{{\partial f_2 }} {{\partial x_2 }},\frac{{\partial f_1 }} {{\partial x_2 }} = - \frac{{\partial f_2 }} {{\partial x_1 }} $$
(7.1)
Heinz-Otto Peitgen, Peter H. Richter
8. A Discrete Volterra-Lotka System
Abstract
In our discussions of Newton’s method we demonstrated how an apparently innocent system of differential equations gives rise to unimaginably rich and complex behaviour after discretization. This is also the Leitmotiv of our last example, the Volterra-Lotka equations for a predator-prey system.
Heinz-Otto Peitgen, Peter H. Richter

Magnetism and Complex Boundaries

Frontmatter

Special Sections

9. Yang-Lee Zeros
Abstract
For those readers familiar with the formalism of canonical statistics, we present here some facts about the location of the Yang-Lee zeros for the Ising model of magnetism.
Heinz-Otto Peitgen, Peter H. Richter
10. Renormalization
Abstract
The idea of renormalization can be understood as a successive thinning out of the degrees of freedom in the partition function. The N-particle problem is transformed into an N’-particle problem with N’ < N, whereby the temperature T and the magnetic field H may also have to be renormalized. Assume in the following that there is no external magnetic field, H–0.
Heinz-Otto Peitgen, Peter H. Richter

References

References
Heinz-Otto Peitgen, Peter H. Richter

Invited Contributions

Fractals and the Rebirth of Iteration Theory
Abstract
No more than six years ago! Only ten and twenty-odd years ago! On many days, I find it hard to believe that only six years have passed since I first saw and described the structure of the beautiful set which is celebrated in the present book, and to which I am honored and delighted that my name should be attached. No more than twenty-odd years have passed since I be­came convinced that my varied forays into unfashionable and lonely corners of the Unknown were not separate enterprises. No one had seen any unity between them, other than provided by my personality; yet, around 1964, they showed promise of consolidating one day into an organized field, which I proceeded to investigate systematically. And no more than ten years have passed since my field had consolidated enough to justify writing a book about it, hence giving it a name, which led me to coin the word fractal geometry. The beauty of many fractals is the more extraordinary for its having been wholly unexpected: they were meant to be mathematical diagrams drawn to make a scholarly point, and one might have expected them to be dull and dry. It is true that the poet wrote that Euclid gazed at beauty bare, but the full and continuing appreciation of the beauty of Euclid demands hard and long train­ing, and perhaps also a special gift. To the contrary, it seems that nobody is in­different to fractals. In fact, many view their first encounter with fractal geome­try as a totally new experience from the viewpoints of aesthetics as well as science. From these viewpoints, fractals are indeed as new as can be.
Benoit B. Mandelbrot
Julia Sets and the Mandelbrot Set
Abstract
Quadratic Julia sets, and the Mandelbrot set, arise in a mathematical situation which is extremely simple, namely from sequences of complex numbers defined inductively by the relation
$$z_n + = z_n^2 + c,$$
where c is a complex constant. I must say that, in 1980, whenever I told my friends that I was just starting with J.H. Hubbard a study of polynomials of degree 2 in one complex variable (and more specifically those of the form z↦z2+c). they would all stare at me and ask: Do you expect to find anything new? It is, however, this simple family of polynomials which is responsible for producing these objects which are so complicated — not chaotic, but on the contrary, rigorously organized according to sophisticated combinatorial laws.
Adrien Douady
Freedom, Science, and Aesthetics
Abstract
This is a most unusual occasion that I have been asked to comment on. It is rather unusual for natural scientists to endeavor with such tenacity to bring their results and insights to the general public, but the form they use here is even more unusual! Instead of giving an abstract presentation in so many dry words, they have chosen pictures with a direct, universal appeal — a combination of mathematics and art!
Gert Eilenberger
Refractions of Science into Art
Abstract
Art critics in the centuries to come will, I expect, look back on our age and come to conclusions quite different than our own experts. Most likely the painters and sculptors esteemed today will nearly have been forgotten, and instead the appearance of electronic media will be hailed as the most significant turn in the history of art. The debut of those first halting and immature attempts to achieve that ancient goal, namely the pictorial expression and representation of our world, but with a new media, will finally be given due recognition.
Herbert W. Franke
Metadaten
Titel
The Beauty of Fractals
verfasst von
Prof. Dr. Heinz-Otto Peitgen
Prof. Dr. Peter H. Richter
Copyright-Jahr
1986
Verlag
Springer Berlin Heidelberg
Electronic ISBN
978-3-642-61717-1
Print ISBN
978-3-642-61719-5
DOI
https://doi.org/10.1007/978-3-642-61717-1