Fractal Attractors in Random Nonlinear Iterated Function Systems: Existence, Stability, and Dimensional Properties
Mohamed Aly Bouke
TL;DR
This work formalizes Random Nonlinear Iterated Function Systems (RNIFS), integrating randomness and nonlinear maps to generate fractal attractors. It proves existence and stability results via a contracted Hutchinson operator on probability measures and a Lyapunov-type condition, and it empirically characterizes attractors using box-counting dimensions across a suite of nonlinear function families. The eight numerical experiments reveal a diverse zoo of self-similar structures with box-counting dimensions spanning roughly $1.43$ to $1.89$, and a case study shows RNIFS extend the classical Sierpiński triangle with increased geometric richness. The findings advance the theory of random fractals and offer a flexible framework for modeling complex stochastic self-similar structures in science and engineering.
Abstract
This study develops a comprehensive theoretical and computational framework for Random Nonlinear Iterated Function Systems (RNIFS), a generalization of classical IFS models that incorporates both nonlinearity and stochasticity. We establish mathematical guarantees for the existence and stability of invariant fractal attractors by leveraging contractivity conditions, Lyapunov-type criteria, and measure-theoretic arguments. Empirically, we design a set of high-resolution simulations across diverse nonlinear functions and probabilistic schemes to analyze the emergent attractors geometry and dimensionality. A box-counting method is used to estimate the fractal dimension, revealing attractors with rich internal structure and dimensions ranging from 1.4 to 1.89. Additionally, we present a case study comparing RNIFS to the classical Sierpiński triangle, demonstrating the generalization's ability to preserve global shape while enhancing geometric complexity. These findings affirm the capacity of RNIFS to model intricate, self-similar structures beyond the reach of traditional deterministic systems, offering new directions for the study of random fractals in both theory and applications.
