Sequential Dynamical System - Definition

Definition

An SDS is constructed from the following components:

  • A finite graph Y with vertex set v = {1,2, ..., n}. Depending on the context the graph can be directed or undirected.
  • A state xv for each vertex i of Y taken from a finite set K. The system state is the n-tuple x = (x1, x2, ..., xn), and x is the tuple consisting of the states associated to the vertices in the 1-neighborhood of i in Y (in some fixed order).
  • A vertex function fi for each vertex i. The vertex function maps the state of vertex i at time t to the vertex state at time t + 1 based on the states associated to the 1-neighborhood of i in Y.
  • A word w = (w1, w2, ..., wm) over v.

It is convenient to introduce the Y-local maps Fi constructed from the vertex functions by

The word w specifies the sequence in which the Y-local maps are composed to derive the sequential dynamical system map F: Kn → Kn as

If the update sequence is a permutation one frequently speaks of a permutation SDS to emphasize this point. The phase space associated to a sequential dynamical system with map F: Kn → Kn is the finite directed graph with vertex set Kn and directed edges (x, F(x)). The structure of the phase space is governed by the properties of the graph Y, the vertex functions (fi)i, and the update sequence w. A large part of SDS research seeks to infer phase space properties based on the structure of the system constituents.

Read more about this topic:  Sequential Dynamical System

Famous quotes containing the word definition:

    “Although there is no universal agreement as to a definition of life, its biological manifestations are generally considered to be organization, metabolism, growth, irritability, adaptation, and reproduction.”
    —The Columbia Encyclopedia, Fifth Edition, the first sentence of the article on “life” (based on wording in the First Edition, 1935)

    “The man who knows governments most completely is he who troubles himself least about a definition which shall give their essence. Enjoying an intimate acquaintance with all their particularities in turn, he would naturally regard an abstract conception in which these were unified as a thing more misleading than enlightening.”
    —William James (1842–1910)

    “I’m beginning to think that the proper definition of “Man” is “an animal that writes letters.””
    —Lewis Carroll [Charles Lutwidge Dodgson] (1832–1898)