--- title: News --- Some reverse chronological news. ## 2026 - *2026-01-28*: With the ICML 2026 deadline, I forgot to mention that together with [Sofiane Tanji](https://sofianetanji.com/) and [Yassine Laguel](https://yassine-laguel.github.io/), we have a new preprint [Fairness-informed Pareto Optimization: An Efficient Bilevel Framework](https://arxiv.org/abs/2601.13448). If you like fairness or multiobjective optimization or bilevel optimization, you won't be disappointed to skim it! - *2026-01-28*: A small Rust tool to monitor new email using IMAP IDLE command [svaiter/imapidle_then](https://github.com/svaiter/imapidle_then) ## 2025 - *2025-12-02*: **NeurIPS 2025 San Diego** -- I will be in San Diego for NeurIPS (December 2-6). - *2025-11-13*: **PhD defense: Léo Davy** -- Léo Davy defended his PhD thesis (supervisors: Nelly Pustelnik and Patrice Abry) that I had the pleasure to review. Congrats! - *2025-11-06*: **Talk at Séminaire Math-IA Bordeaux** -- I gave a talk at the Séminaire Math-IA in Bordeaux on [Geometrical and computational complexity of bilevel optimization](https://www.math.u-bordeaux.fr/fr/agenda/7421). - *2025-10-01*: **Promoted Directeur de recherche** -- Starting today, I am officially promoted [*Directeur de recherche*](https://fr.wikipedia.org/wiki/Directeur_de_recherche_au_CNRS) at CNRS. - *2025-10-01*: **CIRM workshop on inverse problems** -- I am the CIRM this week for the [(Blind) inverse problems in imaging: from foundations to applications](https://conferences.cirm-math.fr/3349.html) workshop organized by Luca, Emmanuel and Pierre. - *2025-09-03*: **New PhD student: Tùng Nguyễn Thanh** -- Tùng Nguyễn Thanh just started his PhD with Yassine Laguel and myself. - *2025-08-11*: **Workshop at Simons Institute Berkeley** -- I am in Berkeley this week for the [Graph Learning Meets Theoretical Computer Science](https://simons.berkeley.edu/workshops/graph-learning-meets-theoretical-computer-science) workshop at the [Simons Institute for the Theory of Computing](https://simons.berkeley.edu/homepage). - *2025-07-14*: **Visiting Rennes** -- I am visiting [Nicolas Keriven](https://nkeriven.github.io) in Rennes this week. - *2025-07-07*: **PhD defense: Sophie Jaffard** -- Sophie Jaffard defended his PhD thesis on [Spiking neural networks : learning as point processes](https://theses.hal.science/tel-05290040v1). Congrats to her! It was a pleasure to supervise her with [Patricia Reynaud-Bouret](https://math.univ-cotedazur.fr/~reynaudb). - *2025-05-20*: **Café Calcul presentation** -- I present at [Café calcul](https://groupe-calcul.cnrs.fr/cafe-ad.html) from Groupe Calcul. I introduce automatic differentiation: from the chain rule and Jacobians to forward and reverse modes (backprop) via computational graphs, showing simple implementations, semantic interpretations, and a glimpse of theory for iterative algorithms. - *2025-04-29*: **Talk at LJAD-MAASAI seminar** -- I gave a talk at the joint seminar between the Probability and Statistics team of the LJAD and the Inria MASAAI team on some advances on nonconvex bilevel optimization. - *2025-04-17*: **Talk at MaLGa Genoa** -- I gave a talk at MaLGa in Genoa, hosted by L. Calatroni. - *2025-04-01*: **Bilevel paper accepted to Math. Prog.** -- Our paper [Geometric and computational hardness of bilevel programming](https://arxiv.org/abs/2407.12372) has been accepted to Math. Prog! - *2025-03-24*: **Talk at GDR IASIS Lyon** -- I give a talk at GDR IASIS day on bilevel optimization in Lyon. - *2025-02-02*: **Oberwolfach workshop** -- I was in Oberwolfach for the Mathematical Imaging and Surface Processing workshop. The [report](https://publications.mfo.de/handle/mfo/4228) is available. - *2025-01-29*: **Winter school Dijon-Besançon** -- I gave a 5-hours introduction to language models at the Winter school Dijon-Besaçon. - *2025-01-13*: **MIA 2025 Conference** -- We organized [MIA 2025 Conference](https://rt-maiages.math.cnrs.fr/mia25/mia25/) in Paris. ## 2024 - *2024-12-16*: **ICSDS 2024 Conference** -- We organized the [ICSDS 2024 Conference](https://www.ims-icsds2024.org/home) in Nice. - *2024-12-10*: **NeurIPS 2024 Vancouver** -- I will be in Vancouver for NeurIPS. - *2024-12-03*: **PhD defense: Matthieu Cordonnier** -- Matthieu Cordonnier defended his PhD thesis on "Neural networks on large scale random graphs". Congrats! - *2024-11-28*: **Talk at SophIA Summit** -- I gave an invited talk at [SophIA Summit](https://univ-cotedazur.eu/events/sophia-summit) - *2024-11-07*: **MPGNN paper accepted to JMLR** -- Our paper [Convergence of Message Passing Graph Neural Networks with Generic Aggregation On Large Random Graphs](https://arxiv.org/abs/2304.11140) was accepted for publication in J. Mach. Learn. Res. - *2024-10-08*: **PhD defense: Mathieu Dagréou** -- [Mathieu Dagréou](https://matdag.github.io) defended his PhD thesis on "Contributions to stochastic bilevel optimization". Congratulations Mathieu! - *2024-09-26*: **Derivatives of SGD accepted to NeurIPS 2024** -- Our (w/ F. Iutzeler & E. Pauwels) paper [Derivatives of Stochastic Gradient Descent](https://arxiv.org/abs/2405.15894) was accepted to NeurIPS 2024. - *2024-09-26*: **3IA chair holder** -- Just learned that I will be a 3IA chair holder for the next 4 years for my project BOGL (Bilevel Optimization for Graph Learning). - *2024-09-23*: **LOCA workshop** -- We organized with L. Calatroni the [LOCA workshop](https://optazur.github.io/loca2024/) in Sophie-Antipolis. - *2024-09-10*: **Talk at SPARNP conference** -- I gave a talk at the [Statistical and Probabilistic Analysis of Random Networks and Processes](https://stamford.uni.lu/events/) conference. - *2024-09-02*: **One Piece of Math a Day** -- Started my tweet serie "One Piece of Math a Day" on [Twitter](https://x.com/vaiter). Also available on my website [here](/one-piece/). - *2024-07-09*: **Talk at Inria Grenoble** -- I gave a talk at Inria Grenoble on automatic differentiation. - *2024-07-01*: **Talk at EURO 2024** -- Attending [EURO 2024](https://euro2024cph.dk). I will give an invited talk in the "Algorithms for machine learning and inverse problems" session. - *2024-06-27*: **ANR MAD grant accepted** -- The grant [ANR MAD](/mad) was just accepted. I will be the PI of the project "Mathematics of Automatic Differentiation" for the next 4 years with the following consortium: J. Bolte, S. Gadat, E. Pauwels (Toulouse School of Economics), G. Fort, F. Iutzeler (Université Paul Sabatier) and J.-B. Caillau, Y. Laguel (Université Côte d'Azur). - *2024-06-23*: **Visiting MILA** -- Visiting [G. Gidel](https://gauthiergidel.github.io) at [MILA](https://mila.quebec). I gave a talk at [MTL Opt](https://mtl-mlopt.github.io). - *2024-06-15*: **Gradient Scarcity accepted to TMLR** -- Accepted paper to TMLR with Hashem Ghanem and Nicolas Keriven [Gradient Scarcity with Bilevel Optimization for Graph Learning](https://openreview.net/forum?id=10YJTIsVYq) with Featured Certification! - *2024-05-28*: **Preprint: CHANI** -- New preprint with Sophie Jaffard and Patricia Reynaud-Bouret [CHANI: Correlation-based Hawkes Aggregation of Neurons with bio-Inspiration](https://arxiv.org/abs/2405.18828). - *2024-05-21*: **Preprint: Derivatives of SGD** -- New preprint with Franck Iutzeler and Edouard Pauwels on the [Derivatives of Stochastic Gradient Descent](https://arxiv.org/abs/2405.15894). - *2024-04-09*: **HVP blogpost spotlight at ICLR 2024** -- Our blogpost with Mathieu Dagréou, Pierre Ablin and Thomas Moreau [How to compute Hessian-vector products?](https://iclr-blogposts.github.io/2024/blog/bench-hvp/) was accepted to ICLR 2024 as *spotlight*. - *2024-03-01*: **Visiting Flatiron Institute NYC** -- Visiting [A. Bietti](https://alberto.bietti.me) at [CCM, Flatiron Institute, NYC](https://www.simonsfoundation.org/flatiron/center-for-computational-mathematics/). I presented our work on iterative automatic differentiation. - *2024-01-24*: **Talk at PEPR PDE-AI kickoff** -- Talk at the kickoff meeting of the [PEPR PDE-AI](https://pde-ai.math.cnrs.fr/) project. - *2024-01-20*: **Two papers accepted to AISTATS 2024** -- Our papers [Provable local learning rule by expert aggregation for a Hawkes network](https://arxiv.org/abs/2304.08061) and [A Lower Bound and a Near-Optimal Algorithm for Bilevel Empirical Risk Minimization](https://arxiv.org/abs/2302.08766) were accepted to AISTATS 2024. ## 2017 - *2017-10-24*: **Graph-Slope paper accepted in EJS** -- Our paper with [Pierre C. Bellec](http://www.stat.rutgers.edu/home/PCB71/) and [Joseph Salmon](http://josephsalmon.eu) coined [A sharp oracle inequality for Graph-Slope](https://arxiv.org/abs/1706.06977) has been accepted in Electronic Journal of Statistics. - *2017-06-21*: **Preprint on Graph-Slope** -- Together with [Pierre C. Bellec](http://www.stat.rutgers.edu/home/PCB71/) and [Joseph Salmon](http://josephsalmon.eu), we released our preprint [A sharp oracle inequality for Graph-Slope](https://arxiv.org/abs/1706.06977). - *2017-04-16*: **Model Consistency of Partly Smooth Regularizers accepted in TIT** -- After two long years in review, our paper with J. Fadili and G. Peyré [Model Consistency of Partly Smooth Regularizers](http://hal.archives-ouvertes.fr/hal-00987293) has been accepted for publication in IEEE Transactions on Information Theory. - *2017-03-20*: **Accelerated alternating descent methods published in JMIV** -- Our paper with A. Chambolle and P. Tan, [Accelerated Alternating Descent Methods for Dykstra-like problems](https://hal.archives-ouvertes.fr/hal-01346532) has been accepted for publication in Journal of Mathematical Imaging and Vision. The online first version is available [here](http://link.springer.com/article/10.1007/s10851-017-0724-6). - *2017-02-14*: **New preprint on non-uniqueness for the analysis Lasso** -- Our work with A. Barbara and A. Jourani on non-uniqueness for the analysis Lasso is available at the following link [Maximal solutions of sparse analysis regularization](https://hal.archives-ouvertes.fr/hal-01467965). ## 2016 - *2016-12-03*: **CLEAR accepted in SIAM IS** -- Our paper on re-fitting has been accepted for publication in SIAM Journal on Imaging Science. The preprint is available at the following link [CLEAR: Covariant LEAst-square Re-fitting with applications to image restoration](https://arxiv.org/abs/1606.05158). - *2016-07-22*: **New preprint on accelerated alternating descent methods** -- Together with A. Chambolle and P. Tan, we extended recent results by Antonin and T. Pock on the acceleration of alternating minimization techniques for quadratic plus nons-mooth objectives depending on two variables, with an emphasis on the strongly convex case. The paper is available at [Accelerated Alternating Descent Methods for Dykstra-like problems](https://hal.archives-ouvertes.fr/hal-01346532). - *2016-06-16*: **New preprint on re-fitting** -- Together with C. Deledalle, N. Papadakis and J. Salmon, we proposed a new framework to remove parts of the systematic errors affecting popular restoration algorithms. This work is available at the following link [CLEAR: Covariant LEAst-square Re-fitting with applications to image restoration](https://arxiv.org/abs/1606.05158). - *2016-04-01*: **Paper accepted** -- Our paper [The Degrees of Freedom of Partly Smooth Regularizers](http://hal.archives-ouvertes.fr/hal-00981634) has been accepted for publication in Annals of the Institute of Statistical Mathematics (AISM). ## 2015 - *2015-11-03*: **MOA Workshop 2015** -- We organize at the [IMB](http://math.u-bourgogne.fr/) the annual workshop of the [GdR MOA](http://gdrmoa.math.cnrs.fr/) in December 2015. It will highlight recent advances in optimization. More information [here](/events/journees-moa-2015). - *2015-10-28*: **PhD PGMO award** -- I received one of the two PGMO PhD award for my thesis. This award is delivered by [Programme Gaspard Monge pour l'optimisation et la recherche opérationnelle](http://www.fondation-hadamard.fr/pgmo.php?url=95.142.164.215/fr/prixthese). - *2015-10-01*: **CNRS** -- My postdoctoral position is over and I am now a CNRS researcher (CR2). I joined the [IMB](http://math.u-bourgogne.fr/) at [Université de Bourgogne](http://www.u-bourgogne.fr/). - *2015-04-02*: **PhD award** -- I received a best PhD award for my thesis. This award is delivered by [Fondation Dauphine](http://www.fondation.dauphine.fr/). - *2015-01-12*: **Two new papers** -- Our paper [Model Selection with Low Complexity Priors](http://hal.archives-ouvertes.fr/hal-00842603) has been accepted for publication Information and Inference (IMAIAI). Moreover, our book chapter [Low Complexity Regularization of Linear Inverse Problems](http://hal.archives-ouvertes.fr/hal-01018927) will be published in *Sampling Theory, a Renaissance* edited by G. Pfander. ## 2014 - *2014-10-01*: **New Position** -- I just started my postdoc with [Antonin Chambolle](http://www.cmap.polytechnique.fr/~antonin/) at the CMAP, Ecole Polytechnique. - *2014-08-19*: **SUGAR** -- Our paper [Stein Unbiased GrAdient estimator of the Risk (SUGAR) for multiple parameter selection](http://hal.archives-ouvertes.fr/hal-00987295) has been accepted for publication in [SIAM Journal on Imaging Sciences](http://www.siam.org/journals/siims.php). - *2014-07-10*: **Ph. D.** -- I successfully defended my PhD dissertation, see [this page](http://samuelvaiter.com/phd/) for more information. - *2014-05-05*: **Preprints on Model Stability and Stein Estimation** -- [Model Consistency of Partly Smooth Regularizers](http://hal.archives-ouvertes.fr/hal-00987293) and [Stein Unbiased GrAdient estimator of the Risk (SUGAR) for multiple parameter selection](http://hal.archives-ouvertes.fr/hal-00987295) are now available online. - *2014-04-22*: **Preprint DOF** -- Our last preprint [The Degrees of Freedom of Partly Smooth Regularizers](http://hal.archives-ouvertes.fr/hal-00981634) is available online.