String Substitution Systems

Stephen Wolfram

(Unfinished draft as of March 28, 2006; with small updates October 2019)

Introduction
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Neighbor-Independent Rules
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Single-Rewrite Neighbor-Dependent Substitution Systems
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Multiple Substitutions
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Examples with Complex Behavior
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Approaches to Analysis
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Long Initial Conditions
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Reversibility
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Emulation
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Algebraic Representations (& Invariances)
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Cyclic (Closed) Strings
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(Unordered Strings)
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Conditional Causal Invariance

Appendix: Implementation
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Code Used
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