Box-Counting: A way of determining the fractal dimension of a set S in a Euclidean space Rn, or more generally in a metric space (X, d).
Critical Phenomena: A wide variety of systems display a common set of behaviors and characteristics when they are at or near a critical point.
Diffusion: The intermixing of two or more substances by the natural movement of their particles.
Fractal Geometry: For example, freezing water tends to form fractal patterns, including snowflakes and other crystal structures. Fractals are characterized by self-similarity; that is, parts of the pattern are similar to scaled copies of the whole.
Percolation: A process in which a fluid flows through a semi-porous material.
Percolation Model: A model used to represent percolation that can be abstracted to be use for epidemic modeling, networks of electrical resistors, and other systems that are not directly percolation.
Phase Change: The rapid change in behavior near the critical value.
Random Walk: A stochastic process consisting of a sequence of changes each of whose characteristics (as magnitude or direction) is determined by chance.