Tiago Pimentel
tpimentel.bsky.social
Tiago Pimentel
@tpimentel.bsky.social
Postdoc at ETH. Formerly, PhD student at the University of Cambridge :)
LLMs are trained to mimic a “true” distribution—their reducing cross-entropy then confirms they get closer to this target while training. Do similar models approach this target distribution in similar ways, though? 🤔 Not really! Our new paper studies this, finding 4-convergence phases in training 🧵
October 1, 2025 at 6:08 PM
Mechanistic interpretability often relies on *interventions* to study how DNNs work. Are these interventions enough to guarantee the features we find are not spurious? No!⚠️ In our new paper, we show many mech int methods implicitly rely on the linear representation hypothesis🧵
July 14, 2025 at 12:15 PM
A string may get 17 times less probability if tokenised as two symbols (e.g., ⟨he, llo⟩) than as one (e.g., ⟨hello⟩)—by an LM trained from scratch in each situation! Our new ACL paper proposes an observational method to estimate this causal effect! Longer thread soon!
June 4, 2025 at 10:51 AM
If you're finishing your camera-ready for ACL or ICML and want to cite co-first authors more fairly, I just made a simple fix to do this! Just add $^*$ to the authors' names in your bibtex, and the citations should change :)

github.com/tpimentelms/...
May 29, 2025 at 8:53 AM
Are you interested in word lengths and natural language’s efficiency? If yes, check out our new #EMNLP2023 paper! It has everything you need: drama, suspense, a new derivation of Zipf’s law, an update to Piantadosi et al’s classic word length paper, transformers... 😄

arxiv.org/abs/2312.03897
December 8, 2023 at 5:46 PM