Saddle-To-Saddle Dynamics in Deep ReLU Networks: Low-Rank Bias in the First Saddle Escape
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Abstract (arXiv)
When a deep ReLU network is initialized with small weights, gradient descent (GD) is at first dominated by the saddle at the origin in parameter space. We study the so-called escape directions along which GD leaves the origin, which play a similar role as the eigenvectors of the Hessian for strict saddles. We show that the optimal escape direction features a low-rank bias in its deeper layers: the first singular value of the ℓ-th layer weight matrix is at least ℓ^frac14 larger than any other singular value. We also prove a number of related results about these escape directions. We suggest that deep ReLU networks exhibit saddle-to-saddle dynamics, with GD visiting a sequence of saddles with increasing bottleneck rank (Jacot, 2023).
Key facts. Cited by 4 papers in the map (data through 7 Oct 2026). Builds on 47 of its 55 references that are in the map. First posted on arXiv 27 May 2025.
Builds on
47 of 55 references.
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35 more
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Built on by
Citing papers per year: 2025: 2; 2026: 2.
4 papers.
- 2025Saddle-to-Saddle Dynamics Explains A Simplicity Bias Across Neural Network Architecturescited by 14
- 2025Alternating Gradient Flows: A Theory of Feature Learning in Two-layer Neural Networkscited by 11
- 2026A Theory of Saddle Escape in Deep Nonlinear Networkscited by 0
- 2026Gradient Flow Dynamics and Implicit Bias of Diagonal Linear Networks under Infinitesimal Initializationcited by 0
- 2026Gradient Flow Dynamics and Implicit Bias of Diagonal Linear Networks under Infinitesimal Initialization14 Jul 2026
- 2026A Theory of Saddle Escape in Deep Nonlinear Networks2 May 2026
- 2025Saddle-to-Saddle Dynamics Explains A Simplicity Bias Across Neural Network Architectures23 Dec 2025
- 2025Alternating Gradient Flows: A Theory of Feature Learning in Two-layer Neural Networks6 Jun 2025