Analytic Insights into Structure and Rank of Neural Network Hessian Maps
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Abstract (arXiv)
The Hessian of a neural network captures parameter interactions through second-order derivatives of the loss. It is a fundamental object of study, closely tied to various problems in deep learning, including model design, optimization, and generalization. Most prior work has been empirical, typically focusing on low-rank approximations and heuristics that are blind to the network structure. In contrast, we develop theoretical tools to analyze the range of the Hessian map, providing us with a precise understanding of its rank deficiency as well as the structural reasons behind it. This yields exact formulas and tight upper bounds for the Hessian rank of deep linear networks, allowing for an elegant interpretation in terms of rank deficiency. Moreover, we demonstrate that our bounds remain faithful as an estimate of the numerical Hessian rank, for a larger class of models such as rectified and hyperbolic tangent networks. Further, we also investigate the implications of model architecture (e.g.~width, depth, bias) on the rank deficiency. Overall, our work provides novel insights into the source and extent of redundancy in overparameterized networks.
Key facts. Cited by 52 papers in the map (data through 7 Oct 2026). Builds on 32 of its 67 references that are in the map. First posted on arXiv 30 Jun 2021.
Builds on
32 of 67 references.
References · 32
- 2015Deep Residual Learning for Image Recognitioncited by 51,809
- 2018BERT: Pre-training of Deep Bidirectional Transformers for Language Understandingcited by 40,204
- 2017Fashion-MNIST: a Novel Image Dataset for Benchmarking Machine Learning Algorithmscited by 4,283
- 2018Neural Tangent Kernel: Convergence and Generalization in Neural Networkscited by 2,597
- 2015Deep Compression: Compressing Deep Neural Networks with Pruning, Trained Quantization and Huffman Codingcited by 2,291
- 2018The Lottery Ticket Hypothesis: Finding Sparse, Trainable Neural Networkscited by 2,250
- 2016On Large-Batch Training for Deep Learning: Generalization Gap and Sharp Minimacited by 1,337
- 2018Reconciling modern machine learning practice and the bias-variance trade-offcited by 919
- 2015Optimizing Neural Networks with Kronecker-factored Approximate Curvaturecited by 776
- 2013Exact solutions to the nonlinear dynamics of learning in deep linear neural networkscited by 748
- 2017Spectrally-normalized margin bounds for neural networkscited by 681
- 2018Measuring the Intrinsic Dimension of Objective Landscapescited by 364
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- 2018Stronger generalization bounds for deep nets via a compression approachcited by 306
- 2015Norm-Based Capacity Control in Neural Networkscited by 299
- 2019An Investigation into Neural Net Optimization via Hessian Eigenvalue Densitycited by 289
- 2017Empirical Analysis of the Hessian of Over-Parametrized Neural Networkscited by 283
- 2018On the Optimization of Deep Networks: Implicit Acceleration by Overparameterizationcited by 280
- 2016Deep Learning without Poor Local Minimacited by 233
- 2017Learning to Prune Deep Neural Networks via Layer-wise Optimal Brain Surgeoncited by 219
- 2018Gradient Descent Happens in a Tiny Subspacecited by 208
- 2018A Convergence Analysis of Gradient Descent for Deep Linear Neural Networkscited by 180
- 2016Eigenvalues of the Hessian in Deep Learning: Singularity and Beyondcited by 156
- 2017Practical Gauss-Newton Optimisation for Deep Learningcited by 139
- 2018Universal Statistics of Fisher Information in Deep Neural Networks: Mean Field Approachcited by 89
- 2019Measurements of Three-Level Hierarchical Structure in the Outliers in the Spectrum of Deepnet Hessianscited by 68
- 2020Practical Quasi-Newton Methods for Training Deep Neural Networkscited by 67
- 2019Shaping the learning landscape in neural networks around wide flat minimacited by 47
- 2017Theory of Deep Learning III: explaining the non-overfitting puzzlecited by 32
- 2019The asymptotic spectrum of the Hessian of DNN throughout trainingcited by 19
- 2021Adaptive Newton Sketch: Linear-time Optimization with Quadratic Convergence and Effective Hessian Dimensionalitycited by 14
- 2020Beyond Random Matrix Theory for Deep Networkscited by 11
- 2021Lower Bounds on the Generalization Error of Nonlinear Learning Modelscited by 6
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Citing papers per year: 2022: 6; 2023: 5; 2024: 12; 2025: 16; 2026: 13.
52 papers.
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- 2023ReLoRA: High-Rank Training Through Low-Rank Updatescited by 200
- 2022Signal Propagation in Transformers: Theoretical Perspectives and the Role of Rank Collapsecited by 136
- 2022Low-rank lottery tickets: finding efficient low-rank neural networks via matrix differential equationscited by 42
- 2024Super Consistency of Neural Network Landscapes and Learning Rate Transfercited by 23
- 2025HybridNorm: Towards Stable and Efficient Transformer Training via Hybrid Normalizationcited by 15
- 2025Sculpting Subspaces: Constrained Full Fine-Tuning in LLMs for Continual Learningcited by 15
- 2022On the Overlooked Structure of Stochastic Gradientscited by 13
- 2025Towards Quantifying the Hessian Structure of Neural Networkscited by 13
- 2023Robust low-rank training via approximate orthonormal constraintscited by 12
- 2024Neglected Hessian component explains mysteries in Sharpness regularizationcited by 12
- 2022Phenomenology of Double Descent in Finite-Width Neural Networkscited by 11
- 2026RMNP: Row-Momentum Normalized Preconditioning for Scalable Matrix-Based Optimizationcited by 11
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- 2024What Does It Mean to Be a Transformer? Insights from a Theoretical Hessian Analysiscited by 9
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- 2025Dynamical Low-Rank Compression of Neural Networks with Robustness under Adversarial Attackscited by 5
- 2025A geometric framework for momentum-based optimizers for low-rank trainingcited by 5
- 2023A PAC-Bayesian Perspective on the Interpolating Information Criterioncited by 4
- 2025Recurrent Self-Attention Dynamics: An Energy-Agnostic Perspective from Jacobianscited by 4
- 2025Optimal Brain Apoptosiscited by 3
- 2025TRACE for Tracking the Emergence of Semantic Representations in Transformerscited by 3
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- 2022Gradient Descent for Low-Rank Functionscited by 2
- 2024Hallmarks of Optimization Trajectories in Neural Networks: Directional Exploration and Redundancycited by 2
- 2025Can Hessian-Based Insights Support Fault Diagnosis in Attention-based Models?cited by 2
- 2025Better Hessians Matter: Studying the Impact of Curvature Approximations in Influence Functionscited by 2
- 2026LoRIF: Low-Rank Influence Functions for Scalable Training Data Attributioncited by 2
- 2024Unraveling the Hessian: A Key to Smooth Convergence in Loss Function Landscapescited by 1
- 2025Accelerating Neural Network Training Along Sharp and Flat Directionscited by 1
- 2025When Active Learning Fails, Uncalibrated Out of Distribution Uncertainty Quantification Might Be the Problemcited by 1
- 2025A Teacher-Student Perspective on the Dynamics of Learning Near the Optimal Pointcited by 1
- 2026Depth, Not Data: An Analysis of Hessian Spectral Bifurcationcited by 1
- 2026Wolkowicz-Styan Upper Bound on the Hessian Eigenspectrum for Cross-Entropy Loss in Nonlinear Smooth Neural Networkscited by 1
- 2023Towards guarantees for parameter isolation in continual learningcited by 0
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- 2024Sampling Foundational Transformer: A Theoretical Perspectivecited by 0
- 2025Closing the Curvature Gap: Full Transformer Hessianscited by 0
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- 2026Curvature-Aligned Probing for Local Loss-Landscape Stabilizationcited by 0
- 2026A Bifurcation Theory Framework for Gradient Descent on the Edge of Stabilitycited by 0
- 2026On the Oracle Complexity of Interpolation-Based Gradient Descentcited by 0
- 2026Closed-Form Steepest Descent Direction toward Flat Minima: Reducing Upper Bounds on the Loss Hessian Eigenspectrum in Neural Networkscited by 0
- 2026Explaining Near-Zero Hessian Eigenvalues Through Approximate Symmetries in Neural Networkscited by 0
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- 2026Explaining Near-Zero Hessian Eigenvalues Through Approximate Symmetries in Neural Networks8 Jul 2026
- 2026Closed-Form Steepest Descent Direction toward Flat Minima: Reducing Upper Bounds on the Loss Hessian Eigenspectrum in Neural Networks27 Jun 2026
- 2026On the Oracle Complexity of Interpolation-Based Gradient Descent18 Jun 2026
- 2026A Bifurcation Theory Framework for Gradient Descent on the Edge of Stability14 Jun 2026
- 2026Optimizer-Model Consistency: Full Finetuning with the Same Optimizer as Pretraining Forgets Less7 May 2026
- 2026Curvature-Aligned Probing for Local Loss-Landscape Stabilization16 Apr 2026
- 2026Wolkowicz-Styan Upper Bound on the Hessian Eigenspectrum for Cross-Entropy Loss in Nonlinear Smooth Neural Networks11 Apr 2026
- 2026RMNP: Row-Momentum Normalized Preconditioning for Scalable Matrix-Based Optimization20 Mar 2026
- 2026Decentralized SGD with Controlled Disagreement Finds Flatter Minima2 Feb 2026
- 2026Depth, Not Data: An Analysis of Hessian Spectral Bifurcation31 Jan 2026
38 more
- 2026LoRIF: Low-Rank Influence Functions for Scalable Training Data Attribution29 Jan 2026
- 2025An Equivariance Toolbox for Learning Dynamics24 Dec 2025
- 2025A Teacher-Student Perspective on the Dynamics of Learning Near the Optimal Point17 Dec 2025
- 2025When Active Learning Fails, Uncalibrated Out of Distribution Uncertainty Quantification Might Be the Problem21 Nov 2025
- 2025Closing the Curvature Gap: Full Transformer Hessians19 Oct 2025
- 2025Better Hessians Matter: Studying the Impact of Curvature Approximations in Influence Functions27 Sep 2025
- 2025A geometric framework for momentum-based optimizers for low-rank training20 Jun 2025
- 2025Can Hessian-Based Insights Support Fault Diagnosis in Attention-based Models?9 Jun 2025
- 2025Recurrent Self-Attention Dynamics: An Energy-Agnostic Perspective from Jacobians26 May 2025
- 2025TRACE for Tracking the Emergence of Semantic Representations in Transformers23 May 2025
- 2025Accelerating Neural Network Training Along Sharp and Flat Directions17 May 2025
- 2025Dynamical Low-Rank Compression of Neural Networks with Robustness under Adversarial Attacks12 May 2025
- 2025Towards Quantifying the Hessian Structure of Neural Networks5 May 2025
- 2025Sculpting Subspaces: Constrained Full Fine-Tuning in LLMs for Continual Learning9 Apr 2025
- 2025HybridNorm: Towards Stable and Efficient Transformer Training via Hybrid Normalization6 Mar 2025
- 2025Optimal Brain Apoptosis25 Feb 2025
- 2025Position: Curvature Matrices Should Be Democratized via Linear Operators31 Jan 2025
- 2024Theoretical characterisation of the Gauss-Newton conditioning in Neural Networks4 Nov 2024
- 2024What Does It Mean to Be a Transformer? Insights from a Theoretical Hessian Analysis14 Oct 2024
- 2024Unraveling the Hessian: A Key to Smooth Convergence in Loss Function Landscapes18 Sep 2024
- 2024Only Strict Saddles in the Energy Landscape of Predictive Coding Networks?21 Aug 2024
- 2024Sampling Foundational Transformer: A Theoretical Perspective11 Aug 2024
- 2024Local vs Global continual learning23 Jul 2024
- 2024Landscaping Linear Mode Connectivity24 Jun 2024
- 2024On Newton's Method to Unlearn Neural Networks20 Jun 2024
- 2024Hallmarks of Optimization Trajectories in Neural Networks: Directional Exploration and Redundancy12 Mar 2024
- 2024Super Consistency of Neural Network Landscapes and Learning Rate Transfer27 Feb 2024
- 2024Provable Emergence of Deep Neural Collapse and Low-Rank Bias in L2-Regularized Nonlinear Networks6 Feb 2024
- 2024Neglected Hessian component explains mysteries in Sharpness regularization19 Jan 2024
- 2023A PAC-Bayesian Perspective on the Interpolating Information Criterion13 Nov 2023
- 2023Towards guarantees for parameter isolation in continual learning2 Oct 2023
- 2023ReLoRA: High-Rank Training Through Low-Rank Updates11 Jul 2023
- 2023Robust low-rank training via approximate orthonormal constraints2 Jun 2023
- 2023The Hessian perspective into the Nature of Convolutional Neural Networks16 May 2023
- 2022On the Overlooked Structure of Stochastic Gradients5 Dec 2022
- 2022Gradient Descent for Low-Rank Functions16 Jun 2022
- 2022Signal Propagation in Transformers: Theoretical Perspectives and the Role of Rank Collapse7 Jun 2022
- 2022Low-rank lottery tickets: finding efficient low-rank neural networks via matrix differential equations26 May 2022
50 newest of 52 All 52 (JSON)
- 2024On Newton's Method to Unlearn Neural Networkscited by 5
- 2024On Newton's Method to Unlearn Neural Networks20 Jun 2024
- 2023ReLoRA: High-Rank Training Through Low-Rank Updatescited by 200
- 2022Signal Propagation in Transformers: Theoretical Perspectives and the Role of Rank Collapsecited by 136
- 2022Low-rank lottery tickets: finding efficient low-rank neural networks via matrix differential equationscited by 42
- 2024Super Consistency of Neural Network Landscapes and Learning Rate Transfercited by 23
- 2025HybridNorm: Towards Stable and Efficient Transformer Training via Hybrid Normalizationcited by 15
- 2025Sculpting Subspaces: Constrained Full Fine-Tuning in LLMs for Continual Learningcited by 15
- 2022On the Overlooked Structure of Stochastic Gradientscited by 13
- 2025Towards Quantifying the Hessian Structure of Neural Networkscited by 13
- 2023Robust low-rank training via approximate orthonormal constraintscited by 12
- 2024Neglected Hessian component explains mysteries in Sharpness regularizationcited by 12
- 2022Phenomenology of Double Descent in Finite-Width Neural Networkscited by 11
- 2026RMNP: Row-Momentum Normalized Preconditioning for Scalable Matrix-Based Optimizationcited by 11
12 most cited of 51 All 51 (JSON)
- 2026Functional Degeneracy in Neural Networks: Measurement and Pruning31 Aug 2026
- 2026Cascading Through the Hierarchy: Regularizer-Induced Feature Detection as Phase Transitions in Deep Linear Neural Networks6 Aug 2026
- 2026Explaining Near-Zero Hessian Eigenvalues Through Approximate Symmetries in Neural Networks8 Jul 2026
- 2026Closed-Form Steepest Descent Direction toward Flat Minima: Reducing Upper Bounds on the Loss Hessian Eigenspectrum in Neural Networks27 Jun 2026
- 2026On the Oracle Complexity of Interpolation-Based Gradient Descent18 Jun 2026
- 2026A Bifurcation Theory Framework for Gradient Descent on the Edge of Stability14 Jun 2026
- 2026Optimizer-Model Consistency: Full Finetuning with the Same Optimizer as Pretraining Forgets Less7 May 2026
- 2026Curvature-Aligned Probing for Local Loss-Landscape Stabilization16 Apr 2026
- 2026Wolkowicz-Styan Upper Bound on the Hessian Eigenspectrum for Cross-Entropy Loss in Nonlinear Smooth Neural Networks11 Apr 2026
- 2026RMNP: Row-Momentum Normalized Preconditioning for Scalable Matrix-Based Optimization20 Mar 2026
- 2026Decentralized SGD with Controlled Disagreement Finds Flatter Minima2 Feb 2026
- 2026Depth, Not Data: An Analysis of Hessian Spectral Bifurcation31 Jan 2026
12 newest of 51 All 51 (JSON)