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Quentin Bertrand

12 accepted papers

2025

On the Closed-Form of Flow Matching: Generalization Does Not Arise from Target Stochasticity

NeurIPS 2025oral

Modern deep generative models can now produce high-quality synthetic samples that are often indistinguishable from real training data. A growing body of research aims to understand why recent methods, such as diffusion and flow matching techniques, generalize so effectively. Among the proposed expla…

Cited by 0SourceScholar
2025

Self-Play $Q$-Learners Can Provably Collude in the Iterated Prisoner's Dilemma

ICML 2025poster

A growing body of computational studies shows that simple machine learning agents converge to cooperative behaviors in social dilemmas, such as collusive price-setting in oligopoly markets, raising questions about what drives this outcome. In this work, we provide theoretical foundations for this ph…

Cited by 0SourcePDFScholar
2024

On the Stability of Iterative Retraining of Generative Models on their own Data

ICLR 2024spotlight

Deep generative models have made tremendous progress in modeling complex data, often exhibiting generation quality that surpasses a typical human's ability to discern the authenticity of samples. Undeniably, a key driver of this success is enabled by the massive amounts of web-scale data consumed by…

2024

Self-Consuming Generative Models with Curated Data Provably Optimize Human Preferences

NeurIPS 2024spotlight

The rapid progress in generative models has resulted in impressive leaps in generation quality, blurring the lines between synthetic and real data. Web-scale datasets are now prone to the inevitable contamination by synthetic data, directly impacting the training of future generated models. Alre…

Cited by 9SourcePDFScholar
2023

On the Limitations of the Elo, Real-World Games are Transitive, not Additive

AISTATS 2023poster

The Elo score has been extensively used to rank players by their skill or strength in competitive games such as chess, go, or StarCraft II. The Elo score implicitly assumes games have a strong additive—hence transitive—component. In this paper, we investigate the challenge of identifying transitive…

Cited by 28SourcePDFScholar
2023

Synergies between Disentanglement and Sparsity: Generalization and Identifiability in Multi-Task Learning

ICML 2023poster

Although disentangled representations are often said to be beneficial for downstream tasks, current empirical and theoretical understanding is limited. In this work, we provide evidence that disentangled representations coupled with sparse task-specific predictors improve generalization. In the cont…

2022

Beyond L1: Faster and Better Sparse Models with skglm

NeurIPS 2022accept

We propose a new fast algorithm to estimate any sparse generalized linear model with convex or non-convex separable penalties. Our algorithm is able to solve problems with millions of samples and features in seconds, by relying on coordinate descent, working sets and Anderson acceleration. It handl…

Cited by 20SourcePDFScholar
2022

The Curse of Unrolling: Rate of Differentiating Through Optimization

NeurIPS 2022accept

Computing the Jacobian of the solution of an optimization problem is a central problem in machine learning, with applications in hyperparameter optimization, meta-learning, optimization as a layer, and dataset distillation, to name a few. Unrolled differentiation is a popular heuristic that approxim…

Cited by 17SourcePDFScholar
2020

Implicit differentiation of Lasso-type models for hyperparameter optimization

ICML 2020poster

Setting regularization parameters for Lasso-type estimators is notoriously difficult, though crucial for obtaining the best accuracy. The most popular hyperparameter optimization approach is grid-search on a held-out dataset. However, grid-search requires to choose a predefined grid of parameters an…

2020

Support recovery and sup-norm convergence rates for sparse pivotal estimation

AISTATS 2020poster

In high dimensional sparse regression, pivotal estimators are estimators for which the optimal regularization parameter is independent of the noise level. The canonical pivotal estimator is the square-root Lasso, formulated along with its derivatives as a “non-smooth + non-smooth” optimization probl…

Cited by 8SourcePDFScholar
2019

Handling correlated and repeated measurements with the smoothed multivariate square-root Lasso

NeurIPS 2019poster

A limitation of Lasso-type estimators is that the optimal regularization parameter depends on the unknown noise level. Estimators such as the concomitant Lasso address this dependence by jointly estimating the noise level and the regression coefficients. Additionally, in many applications, the data…