← Search

Raphaël Berthier

5 accepted papers

2025

Attention layers provably solve single-location regression

ICLR 2025poster

Attention-based models, such as Transformer, excel across various tasks but lack a comprehensive theoretical understanding, especially regarding token-wise sparsity and internal linear representations. To address this gap, we introduce the single-location regression task, where only one token in a s…

2024

On the Minimal Degree Bias in Generalization on the Unseen for non-Boolean Functions

ICML 2024poster

We investigate the out-of-domain generalization of random feature (RF) models and Transformers. We first prove that in the `generalization on the unseen (GOTU)' setting, where training data is fully seen in some part of the domain but testing is made on another part, and for RF models in the small f…

2023

Leveraging the two-timescale regime to demonstrate convergence of neural networks

NeurIPS 2023poster

We study the training dynamics of shallow neural networks, in a two-timescale regime in which the stepsizes for the inner layer are much smaller than those for the outer layer. In this regime, we prove convergence of the gradient flow to a global optimum of the non-convex optimization problem in a s…

2021

Continuized Accelerations of Deterministic and Stochastic Gradient Descents, and of Gossip Algorithms

NeurIPS 2021oral

We introduce the ``continuized'' Nesterov acceleration, a close variant of Nesterov acceleration whose variables are indexed by a continuous time parameter. The two variables continuously mix following a linear ordinary differential equation and take gradient steps at random times. This continuized…

Cited by 24SourcePDFScholar
2020

Tight Nonparametric Convergence Rates for Stochastic Gradient Descent under the Noiseless Linear Model

NeurIPS 2020poster

In the context of statistical supervised learning, the noiseless linear model assumes that there exists a deterministic linear relation $Y = \langle \theta_*, \Phi(U) \rangle$ between the random output $Y$ and the random feature vector $\Phi(U)$, a potentially non-linear transformation of the inputs…

Cited by 55SourcePDFScholar