Structural stability of systems and cycle covers in random graphs
Abstract
Structural system theory studies which network topologies can sustain a prescribed system property such as controllability or stability. When the topology is itself random, the relevant question becomes probabilistic: how likely is a graph drawn from a stochastic model to sustain the property? Such probabilities measure the abundance and robustness of the property across topologies, and indicate whether systems requiring it can be reliably deployed in uncertain environments. We address this question for asymptotic stability of linear systems in the directed graphon setting. We consider two graph-theoretic properties. The first is ๐ฉ, and it requires that for every kโค n some k-vertex induced subdigraph of D admits a cycle cover, and the second is ๐ฎ, which requires that these subdigraphs can be chosen so that their node sets form a nested sequence V1โโฏโ Vn=V(D) starting from a single vertex with a loop. We have shown that ๐ฉ is necessary and ๐ฎ is sufficient for structural stability. We sample D from a directed step-graphon W. Our main results give necessary and sufficient conditions for Pr(๐ฉ)โ 1 and Pr(๐ฎ)โ 1 as nโโ. In more detail, to a step-graphon W with skeleton digraph S on q nodes and concentration vector x* we associate a cycle polytope ๐ณโ(S)โฮq. The conditions are then formulated in terms of the position of x* within ๐ณโ(S), the dimension of the polytope, the loop density of W and, for ๐ฎ, an ordering condition on the cycles of the skeleton. Together these results identify, for directed step-graphons, the regime in which a sampled topology is overwhelmingly likely or unlikely to sustain stable dynamics.
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BibTeX
@misc{belabbas2026structural,
title = {{Structural stability of systems and cycle covers in random graphs}},
author = {Mohamed Ali Belabbas},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.01607},
eprint = {2610.01607},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.01607},
}
RIS
TY - UNPB
TI - Structural stability of systems and cycle covers in random graphs
AU - Mohamed Ali Belabbas
PY - 2026
DA - 2026/10/01
PB - arXiv
DO - 10.48550/arxiv.2610.01607
UR - https://arxiv.org/abs/2610.01607
AB - Structural system theory studies which network topologies can sustain a prescribed system property such as controllability or stability. When the topology is itself random, the relevant question becomes probabilistic: how likely is a graph drawn from a stochastic model to sustain the property? Such probabilities measure the abundance and robustness of the property across topologies, and indicate whether systems requiring it can be reliably deployed in uncertain environments. We address this question for asymptotic stability of linear systems in the directed graphon setting. We consider two graph-theoretic properties. The first is ๐ฉ, and it requires that for every kโค n some k-vertex induced subdigraph of D admits a cycle cover, and the second is ๐ฎ, which requires that these subdigraphs can be chosen so that their node sets form a nested sequence V_1โโฏโ V_n=V(D) starting from a single vertex with a loop. We have shown that ๐ฉ is necessary and ๐ฎ is sufficient for structural stability. We sample D from a directed step-graphon W. Our main results give necessary and sufficient conditions for Pr(๐ฉ)โ 1 and Pr(๐ฎ)โ 1 as nโโ. In more detail, to a step-graphon W with skeleton digraph S on q nodes and concentration vector x^* we associate a cycle polytope ๐ณโ(S)โฮ_q. The conditions are then formulated in terms of the position of x^* within ๐ณโ(S), the dimension of the polytope, the loop density of W and, for ๐ฎ, an ordering condition on the cycles of the skeleton. Together these results identify, for directed step-graphons, the regime in which a sampled topology is overwhelmingly likely or unlikely to sustain stable dynamics.
ER -