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Bibliographic Details
Main Author: Unterberger, Jeremie
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2502.11692
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author Unterberger, Jeremie
author_facet Unterberger, Jeremie
contents We introduce in this article a random model of reactivity in which a primitive rule, if accepted, generates an infinite number of rules by context derivation. The model may be thought of as a toy model of chemical reactivity, where reactions are accepted if their randomly distributed activation energy is below a certain threshold. It may be simulated by induction on the level (length of the word). We describe some statistical features of the model, regarding the number and complexity of the rules, and the shape of the reaction network. The complexity index of a rule is defined as the number of covalent bonds involved in the rearrangement. The Bernoulli parameter (acceptation probability) of the rules is chosen as fixed in a first model (Model I), and exponentially decreasing in the complexity index in a second one (Model II). The two models have very different behaviors, Model II exhibiting a non-trivial phase diagram. The main tool for mathematical analysis is an approximate mapping to a Galton-Watson tree with generation-dependent progeny distributions. Detailed simulations, demonstrating a general agreement with theoretical estimates, are provided at the end. Extensions to realistic bond formation/breaking rules for molecules will be presented elsewhere.
format Preprint
id arxiv_https___arxiv_org_abs_2502_11692
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle An introduction to random rule-based chemical networks
Unterberger, Jeremie
Probability
05C80, 92C42, 92E20
We introduce in this article a random model of reactivity in which a primitive rule, if accepted, generates an infinite number of rules by context derivation. The model may be thought of as a toy model of chemical reactivity, where reactions are accepted if their randomly distributed activation energy is below a certain threshold. It may be simulated by induction on the level (length of the word). We describe some statistical features of the model, regarding the number and complexity of the rules, and the shape of the reaction network. The complexity index of a rule is defined as the number of covalent bonds involved in the rearrangement. The Bernoulli parameter (acceptation probability) of the rules is chosen as fixed in a first model (Model I), and exponentially decreasing in the complexity index in a second one (Model II). The two models have very different behaviors, Model II exhibiting a non-trivial phase diagram. The main tool for mathematical analysis is an approximate mapping to a Galton-Watson tree with generation-dependent progeny distributions. Detailed simulations, demonstrating a general agreement with theoretical estimates, are provided at the end. Extensions to realistic bond formation/breaking rules for molecules will be presented elsewhere.
title An introduction to random rule-based chemical networks
topic Probability
05C80, 92C42, 92E20
url https://arxiv.org/abs/2502.11692