activity
20102026
most citedOn the Number of Linear Regions of Deep Neural Networks

832 citations · 1.3k across the 79 of their papers we have counts for

collaborators

91 papers

cs.LG2026

Polyhedral Geometry of Time-to-First-Spike Neural Networks

Manjot Singh, Guido Montúfar, Gitta Kutyniok

We study the expressivity of spiking neural networks, which provide a natural framework for asynchronous, event-driven computation complementary to conventional feedforward neural…

math.OC2026

The Value Function Semi-Algebraic Set in Partially Observable Markov Decision Processes

Ryan A. Anderson, Guido Montufar

We study the geometry of feasible value functions in infinite-horizon partially observable Markov decision processes (POMDPs) under memoryless stochastic policies. Our main contrib…

cs.LG2026

TriSearch: Learning to Optimize Triangulations via Bistellar Flips

Yiran Wang, Guido Montúfar

We introduce TriSearch, a reinforcement learning framework for optimizing objectives over triangulations of a polytope via bistellar flips. The key idea is a circuit-supported subt…

cs.LG2026

Implicit Bias of Mirror Flow in Homogeneous Neural Networks: Sparse and Dense Feature Learning

Tom Jacobs, Guido Montufar

We study the max-margin solutions reached by mirror flow in deep neural networks with homogeneous activation functions. Extending classical results on gradient flow, we derive a no…

cs.LG2026

Most ReLU Networks Admit Identifiable Parameters

Moritz Grillo, Guido Montúfar

We study the realization map of deep ReLU networks, focusing on when a function determines its parameters up to scaling and permutation. To analyze hidden redundancies beyond these…

cs.LG2026

The Symmetries of Three-Layer ReLU Networks

Johanna Marie Gegenfurtner, Moritz Grillo, Guido Montúfar

We develop a framework for analyzing parameter symmetries in deep ReLU networks and obtain a complete characterization of the generic parameter fibers for three-layer bottleneck ar…

cs.LG2026

Stress-Testing Neural Network Verifiers with Provably Robust Instances

David Troxell, Yulia Alexandr, Sofia Hunt +2

Neural network verifiers aim to provide formal guarantees on model behavior, but existing verification benchmarks are fundamentally limited by their lack of ground-truth labels. As…

cs.LG2026

Differentiable Optimization Layers for Guaranteed Fairness in Deep Learning

David Troxell, Noah Roemer, Guido Montúfar

Differentiable optimization layers are traditionally integrated in predict-then-optimize frameworks where a neural model estimates parameters that subsequently serve as fixed input…

math.AG2026

Algebraic Invariants of Lightning Self-Attention

Yulia Alexandr, Hao Duan, Guido Montúfar

We study the polynomial coefficients of lightning self-attention as coordinates of an algebraic variety. In the single-token case, we characterize the coefficient variety as a rank…

stat.ML2026

Robustness Verification of Polynomial Neural Networks

Yulia Alexandr, Hao Duan, Guido Montúfar

We study robustness verification of neural networks via metric algebraic geometry. For polynomial neural networks, certifying a robustness radius amounts to computing the distance…

stat.ML2026

Harmful Overfitting in Sobolev Spaces

Kedar Karhadkar, Alexander Sietsema, Deanna Needell +1

Motivated by recent work on benign overfitting in overparameterized machine learning, we study the generalization behavior of functions in Sobolev spaces t…

math.AG2025

Hadamard ranks of algebraic varieties

Dario Antolini, Guido Montúfar, Alessandro Oneto

Motivated by the study of decompositions of tensors as Hadamard products (i.e., coefficient-wise products) of low-rank tensors, we introduce the notion of Hadamard rank of a given…

cs.LG2025

Low Rank Gradients and Where to Find Them

Rishi Sonthalia, Michael Murray, Guido Montúfar

This paper investigates low-rank structure in the gradients of the training loss for two-layer neural networks while relaxing the usual isotropy assumptions on the training data an…

cs.LG2025

Gradient Descent with Large Step Sizes: Chaos and Fractal Convergence Region

Shuang Liang, Guido Montúfar

We examine gradient descent in matrix factorization and show that under large step sizes the parameter space develops a fractal structure. We derive the exact critical step size fo…

math.AG2025

Constraining the outputs of ReLU neural networks

Yulia Alexandr, Guido Montúfar

We introduce a class of algebraic varieties naturally associated with ReLU neural networks, arising from the piecewise linear structure of their outputs across activation regions i…

cs.LG2025

Zero-Shot Context Generalization in Reinforcement Learning from Few Training Contexts

James Chapman, Kedar Karhadkar, Guido Montufar

Deep reinforcement learning (DRL) has achieved remarkable success across multiple domains, including competitive games, natural language processing, and robotics. Despite these adv…

stat.ML2025

Understanding Learning Invariance in Deep Linear Networks

Hao Duan, Guido Montúfar

Equivariant and invariant machine learning models exploit symmetries and structural patterns in data to improve sample efficiency. While empirical studies suggest that data-driven…

cs.LG2025

Demystifying Topological Message-Passing with Relational Structures: A Case Study on Oversquashing in Simplicial Message-Passing

Diaaeldin Taha, James Chapman, Marzieh Eidi +2

Topological deep learning (TDL) has emerged as a powerful tool for modeling higher-order interactions in relational data. However, phenomena such as oversquashing in topological me…

cs.LG2024

On the Local Complexity of Linear Regions in Deep ReLU Networks

Niket Patel, Guido Montufar

We define the local complexity of a neural network with continuous piecewise linear activations as a measure of the density of linear regions over an input data distribution. We sh…

stat.ML2024

Bounds for the smallest eigenvalue of the NTK for arbitrary spherical data of arbitrary dimension

Kedar Karhadkar, Michael Murray, Guido Montúfar

Bounds on the smallest eigenvalue of the neural tangent kernel (NTK) are a key ingredient in the analysis of neural network optimization and memorization. However, existing results…

math.OC2024★ 2 cited

Fisher-Rao Gradient Flows of Linear Programs and State-Action Natural Policy Gradients

Johannes Müller, Semih Çaycı, Guido Montúfar

Kakade's natural policy gradient method has been studied extensively in recent years, showing linear convergence with and without regularization. We study another natural gradient…

math.CO2023

Supermodular Rank: Set Function Decomposition and Optimization

Rishi Sonthalia, Anna Seigal, Guido Montufar

We define the supermodular rank of a function on a lattice. This is the smallest number of terms needed to decompose it into a sum of supermodular functions. The supermodular summa…

cs.LG2023

Mildly Overparameterized ReLU Networks Have a Favorable Loss Landscape

Kedar Karhadkar, Michael Murray, Hanna Tseran +1

We study the loss landscape of both shallow and deep, mildly overparameterized ReLU neural networks on a generic finite input dataset for the squared error loss. We show both by co…

cs.LG2023

Function Space and Critical Points of Linear Convolutional Networks

Kathlén Kohn, Guido Montúfar, Vahid Shahverdi +1

We study the geometry of linear networks with one-dimensional convolutional layers. The function spaces of these networks can be identified with semi-algebraic families of polynomi…