# Riddled Basin for Android

 Screenshot 1 Screenshot 2

[How to control]
• By pintching the screen, the set is expanded.

• By pressing the menu button, you can perform the following controls.
• Resize : The default state is restored.
• Change color : You can select the color.
• Magnify rate: You can change the expansion rate.
• Save image : You can save image.
[Description]

Let us treat a two dimensional map written as
xn+1 = xn2 - yn2 -xn - λ yn,
yn+1 = 2xnyn - λ xn + yn.

The variables x and y denote the real part and the imaginary part of the map on the complex plane
zn+1 = zn2 - (1+ λ i) zn*.

In this map, there exists three attractors as shown in the following figure.

The line segments shown in red, green, and blue are the attractors respectively,
and each internal dynamics is chaotic like the logistic map.

The set of points which are attracted to an attractor is called its basin.
This simulator investigates the basins of the above three attractors.
The points in the red area are attracted to the red line segment (attractor), and the whiter color means that the point is attracted to the attractor quickly. The green and blue areas are also painted in the similar manner.

It is observed that the basins of these attractors are intermingled very complexly.
Actually, you can observe the blue and green area by expanding the any region in the red area.

As seen in this simulator, the basin with very complicated structures is called as riddled basin.

For the existence of the riddled basin, it is known that the following conditions are required.
• There exists an invariant submanifold, and its internal dynamics is chaotic.
• The Lyapunov exponent normal to the invariant submanifold is negative, i.e., the submanifold is an attractor.
• There exist other attractors.
These complex properties of the dynamical system are thought to exist ubiquitously in the high-dimensional dynamics.