Position: Spectral GNNs Are Neither Spectral Nor Superior for Node Classification
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Abstract (arXiv)
Spectral Graph Neural Networks (Spectral GNNs) for node classification promise frequency-domain filtering on graphs, yet rest on flawed foundations. Recent work shows that graph Laplacian eigenvectors do not in general have the key properties of a true Fourier basis, but leaves the empirical success of Spectral GNNs unexplained. We identify two theoretical glitches: (1) commonly used "graph Fourier bases" are not classical Fourier bases for graph signals; (2) (n-1)-degree polynomials (n = number of nodes) can exactly interpolate any spectral response via a Vandermonde system, so the usual "polynomial approximation" narrative is not theoretically justified. The effectiveness of GCN is commonly attributed to spectral low-pass filtering, yet we prove that low- and high-pass behaviors arise solely from message-passing dynamics rather than Graph Fourier Transform-based spectral formulations. We then analyze two representative directed spectral models, MagNet and HoloNet. Their reported effectiveness is not spectral: it arises from implementation issues that reduce them to powerful MPNNs. When implemented consistently with the claimed spectral algorithms, performance becomes weak. This position paper argues that: for node classification, Spectral GNNs neither meaningfully capture the graph spectrum nor reliably improve performance; competitive results are better explained by their equivalence to MPNNs, sometimes aided by implementations inconsistent with their intended design.
Key facts. Cited by 1 paper in the map (data through 14 Oct 2026). Builds on 19 of its 38 references that are in the map. First posted on arXiv 19 Mar 2026.
Builds on
19 of 38 references.
References · 19
- 2016Semi-Supervised Classification with Graph Convolutional Networkscited by 11,361
- 2017Inductive Representation Learning on Large Graphscited by 6,320
- 2018How Powerful are Graph Neural Networks?cited by 4,393
- 2017Neural Message Passing for Quantum Chemistrycited by 3,487
- 2016Convolutional Neural Networks on Graphs with Fast Localized Spectral Filteringcited by 2,089
- 2019Simplifying Graph Convolutional Networkscited by 1,477
- 2018CosFace: Large Margin Cosine Loss for Deep Face Recognitioncited by 971
- 2017NormFace: L2 Hypersphere Embedding for Face Verificationcited by 237
- 2021BernNet: Learning Arbitrary Graph Spectral Filters via Bernstein Approximationcited by 195
- 2022How Powerful are Spectral Graph Neural Networkscited by 169
- 2021MagNet: A Neural Network for Directed Graphscited by 107
- 2023Edge Directionality Improves Learning on Heterophilic Graphscited by 90
7 more
- 2024Classic GNNs are Strong Baselines: Reassessing GNNs for Node Classificationcited by 85
- 2023Graph Neural Networks with Learnable and Optimal Polynomial Basescited by 36
- 2023HoloNets: Spectral Convolutions do extend to Directed Graphscited by 20
- 2023Shape-aware Graph Spectral Learningcited by 6
- 2025Graph Few-Shot Learning via Adaptive Spectrum Experts and Cross-Set Distribution Calibrationcited by 3
- 2024Scale-aware Message Passing For Graph Node Classificationcited by 1
- 2025Demystifying MPNNs: Message Passing as Merely Efficient Matrix Multiplicationcited by 1
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Citing papers per year: 2026: 1.
1 paper.