Nirmit Joshi: A Theory of Learning with Autoregressive Chain of Thought

Nirmit Joshi: A Theory of Learning with Autoregressive Chain of Thought

🎙 Nirmit Joshi 👥 3K 📅 August 26, 2025 ⏱ 51 min 👁 206 📄 expert opinion 🧭 2026-08-17
Available in: English (current) Français

Keywords

chain of thoughtlearning theorysample complexitycomputational complexityautoregressive

Summary

The talk presents a theoretical framework for understanding learning with autoregressive chain of thought (CoT) in sequence-to-next-token predictors. The speaker introduces a PAC-style model where a base hypothesis class of next-token predictors is iterated to generate a chain of thought, and the final token is the answer. Two learning settings are compared: end-to-end learning (without observing CoT) and CoT learning (with CoT supervision). The main results show that CoT supervision reduces sample complexity from O(t * VCdim) to O(VCdim * log t), and that time-invariance is crucial for avoiding linear dependence on generation length. Computationally, CoT learning reduces to the base supervised learning problem, while end-to-end learning can be computationally hard even for simple base classes like linear thresholds. The talk concludes with a universality result: any function computable by a time-bounded Turing machine can be learned with CoT using a simple attention-based architecture, suggesting a theoretical justification for the success of transformers with CoT.

155 words

Critical Evaluation

Value of the Information & Strength of the Argument

The talk provides a valuable theoretical contribution by formalizing the learning paradigm of autoregressive chain of thought and deriving sample and computational complexity bounds. The argumentation is clear and rigorous, building on established learning theory concepts. The speaker carefully distinguishes between the benefits of time-invariance and CoT supervision, and provides intuition for the results. The computational separation for linear thresholds is a strong argument for the power of CoT. The universality result is a significant theoretical insight, connecting CoT learning to computational complexity. However, the framework is a simplification and does not address practical aspects like optimization or generalization beyond the realizable setting.

Scientific Rigor, Source Quality, Title Accuracy

The talk is based on a paper available on arXiv (https://arxiv.org/abs/2503.07932) , which is cited in the description. The speaker references prior work, such as Malach’s work on autoregressive learning, and mentions empirical studies on parity tasks. The presentation is scientifically rigorous, with clear definitions and theorems. The title accurately reflects the content. No comments were provided, so no analysis of public reception is possible.

183 words

Title / Content Match

The title accurately reflects the content: the talk presents a theory of learning with autoregressive chain of thought, focusing on sample and computational complexity.

Quality & Reliability

8/10

The talk presents a theoretical framework for learning with autoregressive chain of thought, grounded in established learning theory concepts (PAC, VC dimension, Littlestone dimension). The speaker is a PhD student at TTIC, and the work is based on a paper on arXiv. The presentation is rigorous and well-structured, with clear definitions and results. However, as a seminar talk, it does not provide full proofs or extensive empirical validation, and the framework is a simplified abstraction of real-world training.

Key Moments

Cited Sources

Concurring Sources

Contribution & Novelties

The talk introduces a novel theoretical framework for analyzing learning with autoregressive chain of thought, providing sample and computational complexity bounds that contrast with end-to-end learning. The universality result, showing that attention emerges from CoT learning, is a new explanation for the success of transformers. The framework opens up many open questions for future research.

Pour aller plus loin :

113 words

Radar Profile

The radar profile shows high scores in all dimensions, indicating a technically rigorous and informative talk. The high technical level suggests it is aimed at a specialized audience, but the clear presentation makes it accessible to those with a background in learning theory.

Reliability 8/10