A NEW CLASSIFICATION OF NON-OVERLAPPING SYMMETRIC BINARY FRACTAL TREES USING EPSILON HULLS
This paper presents an analysis of non-overlapping symmetric binary fractal trees using methods of computational topology. In particular, we study the topological aspects of the epsilon-hulls of the trees as epsilon ranges over the non-negative real numbers. The complexity of a tree is defined in terms of the maximum range of the number of levels of holes that can be present for a given ∊. All self-contacting trees have infinite complexity, with the important exceptions of the self-contacting trees with branching angles 90° and 135° (which are space-filling). These two angles have been identified by Mandelbrot and Frame as being topologically critical, and our analysis provides further support to that claim. We will show that for trees with branching angles 90° or 135°, there is a finite upper bound to complexity. For all other branching angles there is no upper bound to complexity. Self-avoiding trees are topologically equivalent because they are all contractible. Our new definition of complexity provides a new way to compare self-avoiding trees.