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Hauptverfasser: Wu, Hongjin, Brandes, Ulrik
Format: Preprint
Veröffentlicht: 2025
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Online-Zugang:https://arxiv.org/abs/2512.21935
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author Wu, Hongjin
Brandes, Ulrik
author_facet Wu, Hongjin
Brandes, Ulrik
contents We study the homogeneous Kuramoto model on a graph and the geometry of its underlying optimization landscape $\min_{\boldsymbol θ\in \mathbb R^n}-\sum_{1\leq i,j\leq n} A_{ij}\cos(θ_i-θ_j).$ This problem admits a dual interpretation. On the one hand, it can be viewed as an unconstrained optimization problem, seeking configurations of points on the unit circle that minimize the energy function. On the other hand, the same function serves as a Lyapunov potential governing the dynamics of the homogeneous Kuramoto model. A central question is to identify which graphs induce a benign energy landscape, in the sense that every second-order stationary point is a global minimizer, corresponding to the fully synchronized state. In this case, the graph is said to be globally synchronizing. Most existing results establish global synchronization by exploiting the fact that the complete graph is globally synchronizing, and by showing that graphs sufficiently close to it inherit this property. In contrast, we uncover a fundamentally different mechanism: on highly-structured graph classes, namely quasi-threshold graphs, global synchronization unfolds through a sequential process of local synchronization that propagates along their underlying skeletons. Our approach relies on a detailed analysis of the phasor geometry at second-order stationary points of the nonconvex energy landscape.
format Preprint
id arxiv_https___arxiv_org_abs_2512_21935
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Benign nonconvexity of synchronization landscape induced by graph skeletons
Wu, Hongjin
Brandes, Ulrik
Combinatorics
Classical Analysis and ODEs
Dynamical Systems
Optimization and Control
90C26, 05C99, 37C75
G.2.2
We study the homogeneous Kuramoto model on a graph and the geometry of its underlying optimization landscape $\min_{\boldsymbol θ\in \mathbb R^n}-\sum_{1\leq i,j\leq n} A_{ij}\cos(θ_i-θ_j).$ This problem admits a dual interpretation. On the one hand, it can be viewed as an unconstrained optimization problem, seeking configurations of points on the unit circle that minimize the energy function. On the other hand, the same function serves as a Lyapunov potential governing the dynamics of the homogeneous Kuramoto model. A central question is to identify which graphs induce a benign energy landscape, in the sense that every second-order stationary point is a global minimizer, corresponding to the fully synchronized state. In this case, the graph is said to be globally synchronizing. Most existing results establish global synchronization by exploiting the fact that the complete graph is globally synchronizing, and by showing that graphs sufficiently close to it inherit this property. In contrast, we uncover a fundamentally different mechanism: on highly-structured graph classes, namely quasi-threshold graphs, global synchronization unfolds through a sequential process of local synchronization that propagates along their underlying skeletons. Our approach relies on a detailed analysis of the phasor geometry at second-order stationary points of the nonconvex energy landscape.
title Benign nonconvexity of synchronization landscape induced by graph skeletons
topic Combinatorics
Classical Analysis and ODEs
Dynamical Systems
Optimization and Control
90C26, 05C99, 37C75
G.2.2
url https://arxiv.org/abs/2512.21935