Feature Learning in L2-regularized DNNs: Attraction/Repulsion and Sparsity
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Abstract (arXiv)
We study the loss surface of DNNs with L2 regularization. We show that the loss in terms of the parameters can be reformulated into a loss in terms of the layerwise activations Zℓ of the training set. This reformulation reveals the dynamics behind feature learning: each hidden representations Zℓ are optimal w.r.t. to an attraction/repulsion problem and interpolate between the input and output representations, keeping as little information from the input as necessary to construct the activation of the next layer. For positively homogeneous non-linearities, the loss can be further reformulated in terms of the covariances of the hidden representations, which takes the form of a partially convex optimization over a convex cone. This second reformulation allows us to prove a sparsity result for homogeneous DNNs: any local minimum of the L2-regularized loss can be achieved with at most N(N+1) neurons in each hidden layer (where N is the size of the training set). We show that this bound is tight by giving an example of a local minimum that requires N2/4 hidden neurons. But we also observe numerically that in more traditional settings much less than N2 neurons are required to reach the minima.
Key facts. Cited by 17 papers in the map (data through 7 Oct 2026). Builds on 20 of its 32 references that are in the map. First posted on arXiv 31 May 2022.
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Citing papers per year: 2022: 2; 2023: 6; 2024: 3; 2025: 4; 2026: 2.
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- 2022Implicit Bias of Large Depth Networks: a Notion of Rank for Nonlinear Functionscited by 38
- 2023On the Stepwise Nature of Self-Supervised Learningcited by 36
- 2023Implicit bias of SGD in L2-regularized linear DNNs: One-way jumps from high to low rankcited by 28
- 2024Mixed Dynamics In Linear Networks: Unifying the Lazy and Active Regimescited by 18
- 2023Variation Spaces for Multi-Output Neural Networks: Insights on Multi-Task Learning and Network Compressioncited by 17
- 2023Bottleneck Structure in Learned Features: Low-Dimension vs Regularity Tradeoffcited by 17
- 2023Mechanism of feature learning in convolutional neural networkscited by 15
- 2024Wide Neural Networks Trained with Weight Decay Provably Exhibit Neural Collapsecited by 14
- 2023How do Minimum-Norm Shallow Denoisers Look in Function Space?cited by 9
- 2025When Diffusion Models Memorize: Inductive Biases in Probability Flow of Minimum-Norm Shallow Neural Netscited by 6
- 2022PathProx: A Proximal Gradient Algorithm for Weight Decay Regularized Deep Neural Networkscited by 2
- 2025On the Cone Effect in the Learning Dynamicscited by 2
5 more
- 2025Understanding Nonlinear Implicit Bias via Region Counts in Input Spacecited by 2
- 2024Hamiltonian Mechanics of Feature Learning: Bottleneck Structure in Leaky ResNetscited by 1
- 2025Phase Transitions between Accuracy Regimes in L2 regularized Deep Neural Networkscited by 0
- 2026On the Learning Dynamics of Two-layer Linear Networks with Label Noise SGDcited by 0
- 2026Theoretical Analysis of Sparse Optimization with Reparameterization, Weight Decay, and Adaptive Learning Ratecited by 0
- 2026Theoretical Analysis of Sparse Optimization with Reparameterization, Weight Decay, and Adaptive Learning Rate24 May 2026
- 2026On the Learning Dynamics of Two-layer Linear Networks with Label Noise SGD11 Mar 2026
- 2025When Diffusion Models Memorize: Inductive Biases in Probability Flow of Minimum-Norm Shallow Neural Nets23 Jun 2025
- 2025Understanding Nonlinear Implicit Bias via Region Counts in Input Space16 May 2025
- 2025Phase Transitions between Accuracy Regimes in L2 regularized Deep Neural Networks10 May 2025
- 2025On the Cone Effect in the Learning Dynamics20 Mar 2025
- 2024Wide Neural Networks Trained with Weight Decay Provably Exhibit Neural Collapse7 Oct 2024
- 2024Mixed Dynamics In Linear Networks: Unifying the Lazy and Active Regimes27 May 2024
- 2024Hamiltonian Mechanics of Feature Learning: Bottleneck Structure in Leaky ResNets27 May 2024
- 2023How do Minimum-Norm Shallow Denoisers Look in Function Space?12 Nov 2023
- 2023Mechanism of feature learning in convolutional neural networks1 Sep 2023
- 2023Bottleneck Structure in Learned Features: Low-Dimension vs Regularity Tradeoff30 May 2023
5 more
- 2023Variation Spaces for Multi-Output Neural Networks: Insights on Multi-Task Learning and Network Compression25 May 2023
- 2023Implicit bias of SGD in L2-regularized linear DNNs: One-way jumps from high to low rank25 May 2023
- 2023On the Stepwise Nature of Self-Supervised Learning27 Mar 2023
- 2022PathProx: A Proximal Gradient Algorithm for Weight Decay Regularized Deep Neural Networks6 Oct 2022
- 2022Implicit Bias of Large Depth Networks: a Notion of Rank for Nonlinear Functions29 Sep 2022
- 2022Implicit Bias of Large Depth Networks: a Notion of Rank for Nonlinear Functionscited by 38
- 2023On the Stepwise Nature of Self-Supervised Learningcited by 36
- 2023Implicit bias of SGD in L2-regularized linear DNNs: One-way jumps from high to low rankcited by 28
- 2024Mixed Dynamics In Linear Networks: Unifying the Lazy and Active Regimescited by 18
- 2023Variation Spaces for Multi-Output Neural Networks: Insights on Multi-Task Learning and Network Compressioncited by 17
- 2023Bottleneck Structure in Learned Features: Low-Dimension vs Regularity Tradeoffcited by 17
- 2023Mechanism of feature learning in convolutional neural networkscited by 15
- 2024Wide Neural Networks Trained with Weight Decay Provably Exhibit Neural Collapsecited by 14
- 2023How do Minimum-Norm Shallow Denoisers Look in Function Space?cited by 9
- 2022PathProx: A Proximal Gradient Algorithm for Weight Decay Regularized Deep Neural Networkscited by 2
- 2025On the Cone Effect in the Learning Dynamicscited by 2
- 2025Understanding Nonlinear Implicit Bias via Region Counts in Input Spacecited by 2
12 most cited of 16 All 16 (JSON)
- 2026Theoretical Analysis of Sparse Optimization with Reparameterization, Weight Decay, and Adaptive Learning Rate24 May 2026
- 2026On the Learning Dynamics of Two-layer Linear Networks with Label Noise SGD11 Mar 2026
- 2025Understanding Nonlinear Implicit Bias via Region Counts in Input Space16 May 2025
- 2025Phase Transitions between Accuracy Regimes in L2 regularized Deep Neural Networks10 May 2025
- 2025On the Cone Effect in the Learning Dynamics20 Mar 2025
- 2024Wide Neural Networks Trained with Weight Decay Provably Exhibit Neural Collapse7 Oct 2024
- 2024Mixed Dynamics In Linear Networks: Unifying the Lazy and Active Regimes27 May 2024
- 2024Hamiltonian Mechanics of Feature Learning: Bottleneck Structure in Leaky ResNets27 May 2024
- 2023How do Minimum-Norm Shallow Denoisers Look in Function Space?12 Nov 2023
- 2023Mechanism of feature learning in convolutional neural networks1 Sep 2023
- 2023Bottleneck Structure in Learned Features: Low-Dimension vs Regularity Tradeoff30 May 2023
- 2023Variation Spaces for Multi-Output Neural Networks: Insights on Multi-Task Learning and Network Compression25 May 2023
12 newest of 16 All 16 (JSON)