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Dylan Foster 🐢

@djfoster.bsky.social
2.5K followers 838 following 113 posts

Incoming professor in EECS and Statistics at UC Berkeley. Principal Researcher @ Microsoft Research NE/NYC. Previously @ MIT, Cornell. AI + RL Foundations. RL Theory Lecture Notes: arxiv.org/abs/2312.16730 dylanfoster.net

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Reposted by Dylan Foster 🐢
RL Theory Virtual Seminars @rl-theory.bsky.social · 08/06/2026
Tomorrow, Zak will talk about his new deep RL method for hard exploration problems. Join us! The talk will be hosted by Csaba.
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Clément Canonne @ccanonne.github.io · 04/06/2026
Huge congratulations to Ilias Diakonikolas, Gautam Kamath, Daniel Kane, Jerry Li, Ankur Moitra, and Alistair Stewart on being awarded the Gödel prize for their breakthrough work on algorithmic robustness! www.sigact.org/prizes/g%C3%...
sigact.org
ACM SIGACT - Gödel Prize
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Chris Paxton @cpaxton.bsky.social · 16/12/2025
New work in why action chunking is so important for robot control (it helps fight compounding error) arxiv.org/abs/2507.09061
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Nathan Lambert @natolambert.bsky.social · 07/12/2025
Building Olmo 3 Think Foundations of Reasoning in Language Models @ NeurIPS 2025 Today 13:45 - 14:30
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let-all.com @let-all.com · 26/11/2025
At #NeurIPS2025? Join us for a Social on Wednesday at 7 PM, featuring a fireside chat with Jon Kleinberg and mentoring tables. Ft. mentors @djfoster.bsky.social @surbhigoel.bsky.social @aifi.bsky.social @gautamkamath.com and more!
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Dylan Foster 🐢 @djfoster.bsky.social · 25/10/2025
The coverage principle: How pre-training enables post-training New preprint where we look at the mechanisms through which next-token prediction produces models that succeed at downstream tasks. The answer involves a metric we call the "coverage profile", not cross-entropy.
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Aviad Rubinstein @aviad-rubinstein.bsky.social · 13/10/2025
The new call for Motwani postdocs application is now open! academicjobsonline.org/ajo/jobs/30865 BTW- Not quite ready for a postdoc? We updated the TCS Masters programs spreadsheet: www.cs.princeton.edu/~smattw/mast... Any career stage and in the (SF) Bay Area? Save the date for TOCA-SV on 11/7!
academicjobsonline.org
Stanford University, Computer Science/Theory Lab/Stanford University
Job #AJO30865, Postdoc in Theoretical Computer Science at Stanford, Computer Science/Theory Lab/Stanford University, Stanford University, Stanford, California, US
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Dylan Foster 🐢 @djfoster.bsky.social · 12/10/2025
Taming Imperfect Process Verifiers: A Sampling Perspective on Backtracking. A totally new framework based on ~backtracking~ for using process verifiers to guide inference, w/ connections to approximate counting/sampling in theoretical CS. Paper: www.arxiv.org/abs/2510.03149
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Dylan Foster 🐢 @djfoster.bsky.social · 02/10/2025
MSR NYC is hiring spring and summer interns in AI/ML/RL! Apply here: jobs.careers.microsoft.com/global/en/jo...
microsoft.com
Microsoft Research Lab - New York City - Microsoft Research
Apply for a research position at Microsoft Research New York & collaborate with academia to advance economics research, prediction markets & ML.
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Miro Dudik @mdudik.bsky.social · 18/09/2025
🚨Microsoft Research NYC is hiring🚨 We're hiring postdocs and senior researchers in AI/ML broadly, and in specific areas like test-time scaling and science of DL. Postdoc applications due Oct 22, 2025. Senior researcher applications considered on a rolling basis. Links to apply: aka.ms/msrnyc-jobs
aka.ms
Microsoft Research Lab - New York City - Microsoft Research
Apply for a research position at Microsoft Research New York & collaborate with academia to advance economics research, prediction markets & ML.
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Dylan Foster 🐢 @djfoster.bsky.social · 12/09/2025
Microsoft Research New York City (www.microsoft.com/en-us/resear...) is seeking applicants for multiple Postdoctoral Researcher positions in ML/AI! These are positions for up to 2 years, starting in July 2026. Application deadline: October 22, 2025
microsoft.com
Microsoft Research Lab - New York City - Microsoft Research
Apply for a research position at Microsoft Research New York & collaborate with academia to advance economics research, prediction markets & ML.
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Dylan Foster 🐢 @djfoster.bsky.social · 27/08/2025
Quick reminder: The deadline for our workshop on Foundations of Reasoning in Language Models (FoRLM) at NeurIPS 2025 is next Wednesday, Sept 3!
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Dylan Foster 🐢 @djfoster.bsky.social · 11/08/2025
Announcing the first workshop on Foundations of Language Model Reasoning (FoRLM) at NeurIPS 2025! 📝Soliciting abstracts that advance foundational understanding of reasoning in language models, from theoretical analyses to rigorous empirical studies. 📆 Deadline: Sept 3, 2025
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Dylan Foster 🐢 @djfoster.bsky.social · 15/07/2025
For those at ICML, Audrey will be presenting this paper at the 4:30pm poster session this afternoon! West Exhibition Hall B2-B3 W-1009
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Reposted by Dylan Foster 🐢
Gautam Kamath @gautamkamath.com · 30/06/2025
ICML's election for their board of directors has begun. I've thrown my hat in the ring. Please consider voting for Gautam Kamath. I have experience with the governance of TMLR, COLT, and ALT, and I think I've demonstrated myself as a consciencious and engaged community member.
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Tom Silver @tomssilver.bsky.social · 29/06/2025
This week's #PaperILike is "The Power of Resets in Online Reinforcement Learning" (Mhammedi et al., 2024). If you're doing RL in sim, why not use the sim to its full potential? Reset to any state! (gym.Env.reset() is not all we need.) PDF: arxiv.org/abs/2404.15417
arxiv.org
The Power of Resets in Online Reinforcement Learning
Simulators are a pervasive tool in reinforcement learning, but most existing algorithms cannot efficiently exploit simulator access -- particularly in high-dimensional domains that require general fun...
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let-all.com @let-all.com · 24/06/2025
📣Join us at COLT 2025 in Lyon for a community event! 📅When: Mon, June 30 | 16:00 CET What: Fireside chat w/ Peter Bartlett & Vitaly Feldman on communicating a research agenda, followed by mentorship roundtable to practice elevator pitches & mingle w/ COLT community! let-all.com/colt25.html
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Eugene Vinitsky 🍒 @eugenevinitsky.bsky.social · 21/06/2025
Hiring a postdoc to scale up and deploy RL-based planning onto some self-driving cars! We'll be building on arxiv.org/abs/2502.03349 and learn what the limits and challenges of RL planning are. Shoot me a message if interested and help spread the word please! Full posting to come in a bit.
arxiv.org
Robust Autonomy Emerges from Self-Play
Self-play has powered breakthroughs in two-player and multi-player games. Here we show that self-play is a surprisingly effective strategy in another domain. We show that robust and naturalistic drivi...
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Jason Hartline @jasonhartline.bsky.social · 09/06/2025
At the IDEAL annual meeting and saw this paper presented. Basically: reducing length of chain of thought LLM computations by deleting intermediate computations, more like classical functional programming where only function call and return values are important. arxiv.org/abs/2503.14337
arxiv.org
PENCIL: Long Thoughts with Short Memory
While recent works (e.g. o1, DeepSeek R1) have demonstrated great promise of using long Chain-of-Thought (CoT) to improve reasoning capabilities of language models, scaling it up during test-time is c...
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Reposted by Dylan Foster 🐢
Clément Canonne @ccanonne.github.io · 04/06/2025
RADEMACHER CHAOS 🤘
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Dylan Foster 🐢 @djfoster.bsky.social · 26/05/2025
Dhruv Rohatgi will be giving a lecture on our recent work on comp-stat tradeoffs in next-token prediction at the RL Theory virtual seminar series (rl-theory.bsky.social) tomorrow at 2pm EST! Should be a fun talk---come check it out!!
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RL Theory Virtual Seminars @rl-theory.bsky.social · 20/05/2025
Later today, Sikata and Marcel will talk about their recent work on oracle-efficient RL with ensembles. Join us!
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Dylan Foster 🐢 @djfoster.bsky.social · 19/05/2025
The abstract submission deadline for FoPt has been extended to the 21st of May (11:59pm UTC). Submission website: openreview.net/group?id=lea...
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Dylan Foster 🐢 @djfoster.bsky.social · 09/05/2025
Announcing the first workshop on Foundations of Post-Training (FoPT) at COLT 2025! 📝 Soliciting abstracts/posters exploring theoretical & practical aspects of post-training and RL with language models! 🗓️ Deadline: May 19, 2025
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Dylan Foster 🐢 @djfoster.bsky.social · 09/05/2025
Announcing the first workshop on Foundations of Post-Training (FoPT) at COLT 2025! 📝 Soliciting abstracts/posters exploring theoretical & practical aspects of post-training and RL with language models! 🗓️ Deadline: May 19, 2025
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Dylan Foster 🐢 @djfoster.bsky.social · 03/05/2025
Is Best-of-N really the best we can do for language model inference? New paper (appearing at ICML) led by the amazing Audrey Huang (ahahaudrey.bsky.social) with Adam Block, Qinghua Liu, Nan Jiang, and Akshay Krishnamurthy (akshaykr.bsky.social). 1/11
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RL Theory Virtual Seminars @rl-theory.bsky.social · 16/04/2025
Last seminars before the summer break: 04/29: Max Simchowitz (CMU) 05/06: Jeongyeol Kwon (Univ. of Widsconsin-Madison) 05/20: Sikata Sengupta & Marcel Hussing (Univ. of Pennsylvania) 05/27: Dhruv Rohatgi (MIT) 06/03: David Janz (Univ. of Oxford) 06/10: Nneka Okolo (MIT)
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Carlo Sferrazza @carlosferrazza.bsky.social · 17/04/2025
What is the place of exploration in today's AI landscape and in which settings can exploration algorithms address current open challenges? Join us to discuss this at our exciting workshop at @icmlconf.bsky.social 2025: EXAIT! exait-workshop.github.io #ICML2025
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Dylan Foster 🐢 @djfoster.bsky.social · 27/03/2025
Reinforcement learning has led to amazing breakthroughs in reasoning (e.g., R1), but can it discover truly new behaviors not already present in the base model? A new paper with Zak Mhammedi and Dhruv Rohatgi: The Computational Role of the Base Model in Exploration arxiv.org/abs/2503.07453
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RL Theory Virtual Seminars @rl-theory.bsky.social · 24/03/2025
Join us tomorrow to attend Vlad's presentation! Related to the seminar from last week, but this time in the offline setting. Tuesday March 25, 6 PM UTC.
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augustychen.bsky.social @augustychen.bsky.social · 10/03/2025
Excited to share new paper: Efficiently Escaping Saddle Points under Generalized Smoothness via Self-Bounding Regularity Link: arxiv.org/abs/2503.04712 Work with Karthik Sridharan and two great undergrads at Cornell, Daniel Yiming Cao and Benjamin Tang 1/8
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arXiv cs.LG Machine Learning @cslg-bot.bsky.social · 11/03/2025
Dylan J. Foster, Zakaria Mhammedi, Dhruv Rohatgi: Is a Good Foundation Necessary for Efficient Reinforcement Learning? The Computational Role of the Base Model in Exploration arxiv.org/abs/2503.07453 arxiv.org/pdf/2503.07453 arxiv.org/html/2503.07453
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let-all.com @let-all.com · 10/03/2025
We have a new blog post on reinforcement learning theory for language model post training! By Akshay Krishnamurthy (@akshaykr.bsky.social) and Audrey Huang (@ahahaudrey.bsky.social)! www.let-all.com/blog/2025/03...
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Michele Guindani @mguindani.bsky.social · 08/03/2025
Congratulations to @lestermackey.bsky.social for receiving the 2025 COPSS Award! 🎉👏 Lester is currently the Chair of the Section on Bayesian Statistical Sciences (SBSS) of the American Statistical Association.
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Dylan Foster 🐢 @djfoster.bsky.social · 23/02/2025
Computational-Statistical Tradeoffs at the Next-Token Prediction Barrier arxiv.org/abs/2502.12465 New paper (another fun internship project!) with Dhruv Rohatgi, Adam Block, Audrey Huang (ahahaudrey.bsky.social), and Akshay Krishnamurthy (akshaykr.bsky.social). 1/11
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Dylan Foster 🐢 @djfoster.bsky.social · 20/02/2025
What are the minimal supervised learning primitives required to perform RL efficiently? New paper led by my amazing intern Dhruv Rohatgi: Necessary and Sufficient Oracles: Toward a Computational Taxonomy for Reinforcement Learning arxiv.org/abs/2502.08632 1/
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arXiv cs.LG Machine Learning @cslg-bot.bsky.social · 19/02/2025
Dhruv Rohatgi, Adam Block, Audrey Huang, Akshay Krishnamurthy, Dylan J. Foster: Computational-Statistical Tradeoffs at the Next-Token Prediction Barrier: Autoregressive and Imitation Learning und... arxiv.org/abs/2502.12465 arxiv.org/pdf/2502.12465 arxiv.org/html/2502.12465
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Mark Riedl @markriedl.bsky.social · 08/02/2025
What kind of policy optimization is this?
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Eugene Vinitsky 🍒 @eugenevinitsky.bsky.social · 24/01/2025
One of the reasons LLMs make RL fun again is: 1) They make efficient exploration and low sample complexity genuinely matter 2) They give us good base policies so less time flailing around
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Maxim Raginsky @mraginsky.bsky.social · 22/01/2025
It’s finally out — and I got to blurb it!
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Eugene Vinitsky 🍒 @eugenevinitsky.bsky.social · 20/01/2025
Finally finally finally some scaling curves for imitation learning in the large-scale-data regime: arxiv.org/abs/2411.04434
arxiv.org
Scaling Laws for Pre-training Agents and World Models
The performance of embodied agents has been shown to improve by increasing model parameters, dataset size, and compute. This has been demonstrated in domains from robotics to video games, when generat...
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Miro Dudik @mdudik.bsky.social · 16/01/2025
📣My team at Microsoft Research New York is hiring a senior researcher in AI, both broadly in AI/ML, and in some specific areas including science of deep learning and modular transfer learning. Apply by February 7, 2025 on the link below. jobs.careers.microsoft.com/global/en/jo...
jobs.careers.microsoft.com
Search Jobs | Microsoft Careers
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RL Theory Virtual Seminars @rl-theory.bsky.social · 05/01/2025
Happy new year! Upcoming: 01/07: Jean Tarbouriech 01/14: Adrienne Tuynman 01/21: Victor Boone 02/18: Itai Sufaro 02/25: Jongmin Lee 03/04: Dhruv Rohatgi 03/11: David Cheikhi 03/18: Zakaria Mhammedi 03/25: Vlad Tkachuk
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Csaba Szepesvari @skiandsolve.bsky.social · 19/12/2024
If you are into ML theory (RL or not) with a proven track record, and you are interested in an industry research position, PM me. Feel free to spread the word.
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Dylan Foster 🐢 @djfoster.bsky.social · 14/12/2024
Given a high-quality verifier, language model accuracy can be improved by scaling inference-time compute (e.g., w/ repeated sampling). When can we expect similar gains without an external verifier? New paper: Self-Improvement in Language Models: The Sharpening Mechanism arxiv.org/abs/2412.01951
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Dylan Foster 🐢 @djfoster.bsky.social · 13/12/2024
Preaching THE POWER OF RESETS with Zak! Poster 6402 in the West ballroom
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Microsoft Research @msftresearch.bsky.social · 13/12/2024
In their 2024 NeurIPS paper on RL under latent dynamics, researchers examine whether existing algorithms designed for simple RL problems can be used to solve more complex RL problems. Dylan Foster discusses the modular approach his team explored. www.microsoft.com/en-us/resear...
 Illustrated image of Dylan Foster “Abstracts: A Microsoft Research Podcast” runs along the bottom.
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Dylan Foster 🐢 @djfoster.bsky.social · 11/12/2024
Happening now!
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Dylan Foster 🐢 @djfoster.bsky.social · 10/12/2024
www.microsoft.com/en-us/resear... Did this short MSR podcast about our paper arxiv.org/abs/2410.17904 on modular approaches to RL with latent dynamics!
microsoft.com
Abstracts: NeurIPS 2024 with Dylan Foster - Microsoft Research
In their 2024 NeurIPS paper on RL under latent dynamics, researchers examine whether existing algorithms designed for simple RL problems can be used to solve more complex RL problems. Dylan Foster dis...
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Dylan Foster 🐢 @djfoster.bsky.social · 08/12/2024
Heading to neurips! Stop by and say hi if you're around.
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