Words on two letters, or their equivalent representation by : sequences, label the branches of the inverse graph of the n th iterate of the parabolic map p `(x) = `x(2&x) of the real line. The abstract properties of words control the evolution of this graph in the content parameter `. In particular,
Discrete models of growth and dynamical percolation in chemistry
β Scribed by Simon J. Fraser
- Publisher
- John Wiley and Sons
- Year
- 1987
- Tongue
- English
- Weight
- 830 KB
- Volume
- 8
- Category
- Article
- ISSN
- 0192-8651
No coin nor oath required. For personal study only.
β¦ Synopsis
Space-time lattice (cellular automaton) models of pattern formation and growth are described. Suitable local rules for automaton evolution represent the spreading of wave fronts of activity in an excitable medium. A random distribution of seeds produces expanding rings that fuse and are annihilated. The seeding density, p A , is used as a scaling parameter to give unique, reduced dynamics in an arbitrary dimensiop d . For d = 2, in this (continuum) picture, the rings fuse globally (percolate) at a critical instant, t , = 0.45. For the unscaled time evolution, dynamical percolation is examined in the pa x t plane. A swath of these percolating states is found. On the "explosion" boundary of this swath the percolation cluster just forms; on the "implosion" boundary it breaks up. Using a small-sample method the fractal dimension of the critical (boundary) cluster is estimated to be 1.9 (+0.01). Also percolation for continuously emitting seeds, which produce 'rdiscs'' of activity, is related to ring evolution.
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