260 likes | 294 Views
The infinitely complex… Fractals. Jennifer Chubb Dean’s Seminar November 14, 2006 Sides available at http://home.gwu.edu/~jchubb. Fractals are about all about infinity…. The way they look, The way they’re created, The way we study and measure them…
E N D
The infinitely complex… Fractals Jennifer Chubb Dean’s Seminar November 14, 2006 Sides available at http://home.gwu.edu/~jchubb
Fractals are about all about infinity… • The way they look, • The way they’re created, • The way we study and measure them… underlying all of these are infinite processes.
Fractal Gallery 3-Dimensional Cantor Set
Fractal Gallery Koch Snowflake Animation
Fractal Gallery Sierpinski’s Carpet Menger Sponge
Fractal Gallery The Julia Set
Fractal Gallery The Mandelbrot Set
Dynamically Generated Fractals and Chaos • Chaotic Pendulum http://www.myphysicslab.com/pendulum2.html
Fractal Gallery Henon Attractor http://bill.srnr.arizona.edu/classes/195b/henon.htm
Fractal Gallery Tinkerbell Attractor and basin of attraction
Fractal Gallery Lorenz Attractor
Fractal Gallery Rossler Attractor
Fractal Gallery Wada Basin
Fractal Gallery Romanesco – a cross between broccoli and cauliflower
What is a fractal? • Self similarity As we blow up parts of the picture, we see the same thing over and over again…
What is a fractal? • So, here’s another example of infinite self similarity… and so on … But is this a fractal?
What is a fractal? • No exact mathematical definition. • Most agree a fractal is a geometric object that has most or all of the following properties… • Approximately self-similar • Fine structure on arbitrarily small scales • Not easily described in terms of familiar geometric language • Has a simple and recursive definition • Its fractal dimension exceeds its topological dimension
Dimension Topological Dimension • Points (or disconnected collections of them) have topological dimension 0. • Lines and curves have topological dimension 1. • 2-D things (think filled in square) have topological dimension 2. • 3-D things (a solid cube) have topological dimension 3.
Dimension Topological Dimension 0 The Cantor Set (3D version as well)
Dimension Topological Dimension 1 Koch Snowflake Chaotic Pendulum, Henon, and Tinkerbell attractors Boundary of Mandelbrot Set
Dimension Topological Dimension 2 Lorenz Attractor Rossler Attractor
Dimension • What is fractal dimension? There are different kinds: • Hausdorff dimension… how does the number of balls it takes to cover the fractal scale with the size of the balls? • Box-counting dimension… how does the number of boxes it takes to cover the fractal scale with the size of the boxes? • Information dimension… how does the average information needed to identify an occupied box scale? • Correlation dimension… calculated from the number of points used to generate the picture, and the number of pairs of points within a distance ε of each other. This list is not exhaustive!
Box-counting dimension Computing the box-counting dimension… … … … … and so on… 1.26186
Hausdorff Dimension of some fractals… • Cantor Set… 0.6309 • Henon Map… 1.26 • Koch Snowflake… 1.2619 • 2D Cantor Dust… 1.2619 • Appolonian Gasket… 1.3057 • Sierpinski Carpet… 1.8928 • 3D Cantor Dust… 1.8928 • Boundary of Mandelbrot Set… 2 (!) • Lorenz Attractor… 2.06 • Menger Sponge… 2.7268