Dimitris Papailiopoulos

@dimitrisp.bsky.social

Researcher @MSFTResearch; Prof @UWMadison (on leave); learning in context; thinking about reasoning; babas of Inez Lily. https://papail.io

LLMs learn world models, beyond a reasonable doubt. It's been the case since GPT-3, but now it should be even more clear. Without them "Guess and Check" would not work. The fact that these "world models" are approximate/incomplete does not disqualify them.

Is 1948 widely acknowledged as the birth of language models and tokenizers? In "A Mathematical Theory of Communication", almost as an afterthought Shannon suggests the N-gram for generating English, and that word level tokenization is better than character level tokenization.

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🎉The Phi-4 reasoning models have landed on HF and Azure AI Foundry. The new models are competitive and often outperform much larger frontier models. It is exciting to see the reasoning capabilities extend to more domains beyond math, including algorithmic reasoning, calendar planning, and coding.

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Re: The Chatbot Arena Illusion Every eval chokes under hill climbing. If we're lucky, there’s an early phase where *real* learning (both model and community) can occur. I'd argue that a benchmark’s value lies entirely in that window. So the real question is what did we learn?

Fun trivia now that “sycophant” became common language to describe LLMs flattering users: In Greek, συκοφάντης (sykophántēs) most typically refers to a malicious slanderer, someone spreading lies, not flattery! Every time you use it, you’re technically using it wrong :D

o3 can't multiply beyond a few digits... But I think multiplication, addition, maze solving and easy-to-hard generalization is actually solvable on standard transformers... with recursive self-improvement Below is the acc of a tiny model teaching itself how to add and multiply

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🚀 🇬🇷 A year in the making! I’ve just completed a set of 21 lectures in Machine Learning, in Greek, designed for high school students. The course introduces key ML concepts, coding in Python & PyTorch, and real-world AI applications. 👉 WebPage: tinyurl.com/ye2awe8m 🎥 YouTube: tinyurl.com/2wwjru6z

Μηχανική Μάθηση (Machine Learning) - YouTube

Διαλέξεις Τεχνητής Νοημοσύνης και Μηχανικής Μάθησης: https://caramanis.github.io/MachineLearningClass/ Καλωσορίσατε στο μάθημα τεχνητής νοημοσύνης και μηχανι...

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If you wanted to collect 1 mil reasoning traces from human subjects on say math, that would cost ~$50m, assuming ~50$/person/hour. Interesting to compare with the cost to generate them from a reasoning LLM, with say with cost per trace ~$0.5 (say 10k tokens).. That's 100x cheaper

2014 GoogLeNet: The best image classifier was only trainable using weeks of Google's custom infrastructure. 2018 ResNet: A more accurate model is trainable in a 1/2 hour on a single GPU. What stops this from happening for LLMs?

Ben Recht@beenwrekt.bsky.social · 2y ago

Machine learning progresses when complicated breakthroughs are soon dramatically simplified as people figure out the salient parts. What a world we're in where this well-trodden pattern rocks financial markets and escalates geopolitical conflict.

A strong math/theory foundation can be extremely useful for ML research. Not for proving sample complexity bounds on "AGI", but for offering a mental model of inaccessible and complex systems, that can allow for accurate predictions, without running expensive experiments.

The "deepseek distilled o1" is an intellectually vacuous discussion, precisely because what they reported in the R1 paper is a reproducible phenomenon! By now many experiments on non-deepseek models show that acc and inf-time compute increase as the result of outcome-based RL.

GRPO and outcome based RL rely heavily on a verifier with access to ground truth data. But likely can work beyond strictly verifiable domains, as long as you have access to a "weak" grader. And perhaps even beyond that, if "correct trajectories" share a common fingerprint..

1/5 A hypothesis on the emergence of long form "yapping" in reasoning models: The increase of "yapping" in reasoning models, as they are trained for more rounds of RL, "emerges" (sorry :D) as models discover that verbose reasoning helps them achieve better rewards (eg higher acc).

I love finding silly tests that LLMs are terrible at. Here's a new one for me: Drawing with Logo (yes the turtle)! To be fair drawing with Logo is hard. But.. here goes 8 examples with sonnet 3.6 vs o1. Example 1/8: Draw the letter G

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resolutions for 2025 - be a good dad and partner - do more nature stuff - walk & run more - spend more time in the water - think deeper - read good books, don’t feel bad not finishing all - be a good mentor & colleague - figure out what reasoning is - don’t be reward hacking - have fun All doable

When we expect an LLM to perform algorithm A on an input X, the prompt to the model should be of sufficient specificity and complexity in order to uniquely identify and run A, among all the possible other algorithms, and their superpositions, that the model can implement.

I've been thinking about in-context learning for nearly 3 years. While there is still plenty I don't fully understand, five papers have--to a very large extent--shaped my perspective on it, and I believe everyone should read them.