Authors: Junyou Zhu, Langzhou He, Fenying Cai, Christian Nauck, Ping Xiong, Chao Gao, Philip S. Yu, Klaus-Robert Müller, +2 more
Organizations: Department of Complexity Science, Potsdam Institute for Climate Impact Research, 14473 Potsdam, Germany · Machine Learning Group, Technical University of Berlin, 10587 Berlin, Germany · Department of Computer Science, University of Illinois at Chicago, Chicago, IL 60607, USA · School of Artificial Intelligence, Optics and Electronics (iOPEN), Northwestern Polytechnical University, Xi’an 710072, China · Berlin Institute for the Foundations of Learning and Data (BIFOLD), 10587 Berlin, Germany · Department of Artificial Intelligence, Korea University, Seoul 136-713, South Korea · Max Planck Institute for Informatics, 66123 Saarbrücken, Germany · Research Institute of Intelligent Complex Systems, Fudan University, Shanghai 200433, China · Department of Physics, Humboldt University Berlin, 12489 Berlin, Germany
In deep graph neural networks, increasing depth enlarges the receptive field but often leads to over-smoothing, where node representations tend to align. We develop a unified, mode-wise stability framework for deep GNN propagation that provides a principled characterization of over-smoothing. By interpreting layer depth as time and layer updates as graph-coupled dynamics, over-smoothing can be understood as an undesirable dynamical synchronization of features, for which the master stability curve provides a theoretical tool to assess the stability of synchrony. Guided by this theory, we further propose Stability-Shaped Deep Graph Learning (SDGL) to mitigate over-smoothing in deep GNNs. SDGL has two complementary instantiations: one induces controlled Turing instability to replace synchronization with spatial pattern formation, and the other maintains stable near-critical propagation. Experiments on diverse node- and graph-level benchmarks demonstrate the improved depth scaling and consistent accuracy gains over strong baselines, including graphs exhibiting long-range dependencies.
Figures & tables
Fig. 1: (a) Over-smoothing as synchronization: node representations H collapse toward a shared state and deviations from synchrony shrink in the middle panel. (b) Our master-stability view: the curve Λ(μ) shows how each graph frequency μ is damped or amplified. Heat-kernel diffusion is strongly contractive at high frequencies (I), our SDGL-DI opens a band-limited amplification window (II), and SDGL-NC remains stable but near-critical (III).
Fig. 2: Overview of our theory. (a) A deep GNN can be viewed as local update f coupled by graph mixing G . (b) We study over-smoothing by tracking the deviation from an all-nodes-equal state H⋆ : ΔH(t)=H(t)−H⋆ ; over-smoothing means ∥ΔH(t)∥→0 as depth grows. (c) Linearizing at H⋆ and diagonalizing G turn the coupled system into independent graph-frequency modes ξ˙k=(J−μkC)ξk . (d) The master stability curve Λ(μ) predicts per-mode growth/decay and highlights three behaviors: (I) strong decay (diffusion over-smoothing), (II) band-limited growth (patterning), and (III) weak decay (near-critical, deep but stable).
Fig. 3: Qualitative dynamics analysis. Starting from random noise, we run 150 layers and visualize the resulting scalar field with a shared color scale. GCN collapses toward a near-constant field (over-smoothing). Our SDGL-DI produces sharp Turing-like patterns via diffusion-induced instability. SDGL-NC preserves non-trivial variation under stable near-critical propagation.
Dataset
Cora
CiteSeer
PubMed
Coauthor-CS
Computers
Photo
GAT
83.03±0.72
72.53±0.54
79.0±0.30
89.51±0.54
86.90±0.32
92.56±0.40
GCN
81.53±0.53
70.32±0.58
79.04±0.37
90.98±0.42
86.49±0.51
92.42±0.23
GraphSAGE
79.37±1.70
67.31±1.63
75.52±2.19
90.62±0.42
76.42±7.60
88.71±2.68
SAN
77.98±1.31
66.30±0.88
74.68±0.81
94.51±0.15
89.93±0.16
94.86±0.10
GTN
78.60±1.72
68.80±1.69
76.90±0.77
−
−
−
GRAND
82.83±1.31
70.26±1.46
78.89±1.96
90.10±0.78
82.79±0.54
91.51±0.41
TABLE I: Classification accuracy (%) on homophilic datasets. We report mean ± std. Best in bold, second-best underlined. “–” denotes data that is out of memory or not included in the original paper
Dataset
#V
#E
#Features
#Classes
Transductive node classification
Cora
2,708
10,556
1,433
7
CiteSeer
3,327
9,104
3,703
6
PubMed
19,717
88,648
500
3
Amazon-Computers
13,752
491,722
767
10
Amazon-Photo
7,650
238,162
745
8
TABLE II: Dataset statistics. For node classification, we report the number of nodes (#V), edges (#E), input feature dimension, and classes. For FakeNewsNet graph classification, we report the corresponding statistics after preprocessing.
Dataset
Actor
Squirrel
Chameleon
GAT
29.05±0.80
30.08±1.03
53.22±1.56
GCN
28.38±0.96
28.87±1.55
49.32±1.88
GraphSAGE
34.88±1.19
36.90±1.03
48.03±2.22
SAN
32.94±0.92
37.00±1.28
51.80±1.95
GTN
35.42±1.50
36.45±1.72
55.84±4.08
GCNII
33.80±1.41
38.74±1.20
59.14±3.49
TABLE III: Classification accuracy (%) on heterophilic datasets. We report mean ± std.
Fig. 4: Accuracy as a function of layer number on two representative node classification benchmarks. (a) Homophilic dataset: Photo. (b) Heterophilic dataset: Chameleon. GCN and GAT degrade substantially as depth increases, whereas both SDGL variants remain stable and competitive even at 30–60 layers. This supports our claim that stability shaping improves depth scaling under both homophilic and heterophilic graph conditions.
Fig. 5: Depth evolution of Dirichlet energy E(H(n)) in log scale from random initialization over 100 layers. GCN and GAT rapidly drive E(H(n)) toward 0 , indicating over-smoothing, while our SDGL-NC keeps E nearly constant and our SDGL-DI increases E and then levels off, consistent with near critical propagation and band-limited amplification.
Fig. 6: Validation of near critical propagation. Spectral gain profiles of our SDGL-NC compared with a diffusion-only heat kernel on Actor and Cora. Left panels plot the spectral radius ρ(T(μ)) , and right panels plot the depth-amplified gain ρ(T(μ))L with L=15 . Our SDGL-NC stays closer to the critical boundary ρ=1 and retains substantially larger deep gain across frequencies, while the heat kernel rapidly suppresses nontrivial modes.
Layers
SDGL-NC (Ours)
SDGL-DI (Ours)
GCN
GAT
3
0.196
0.195
0.113
1.826
10
0.203
0.201
0.229
9.187
30
0.224
0.216
0.559
30.220
60
0.255
0.239
1.054
61.770
TABLE VI: Trainable parameter counts (in millions) as a function of depth on Photo. For all models, we fix the hidden width (and the number of attention heads for GAT) and vary only the number of propagation layers.
Appendix figures & tables1 asset
Supplementary material from the paper’s appendix.
Appendix
SDGL-DI
SDGL-NC
Dataset
Number of layers L
d
Dropout p
lr
Number of layers L
d
Dropout p
lr
Node classification (homophilic)
Cora
15
128
0.39
0.0031
15
128
0.39
0.0094
CiteSeer
10
512
0.40
0.0026
8
64
0.40
0.0020
PubMed
10
256
0.36
0.0044
10
128
0.39
0.0031
Coauthor-CS
8
128
0.52
0.0020
8
128
0.40
0.0020
Appendix
TABLE VII: Hyperparameter disclosure for SDGL across datasets. L is the number of layers, d is the hidden width per field (so the output width is 2d ), p is the dropout rate, and lr is the learning rate.
School of Mathematics and Statistics, Shandong University, Weihai, Shandong 264209, China · Academy of Mathematics and Systems Science, Chinese Academy of Sciences and also with the University of Chinese Academy of Sciences, Beijing 100190, China