arXiv Machine Learning

Tight Sample Complexity of Transformers

arXiv:2606. 09731v1 Announce Type: new Abstract: We tightly characterize the VC dimension of depth-$L$ Transformers with a total of $W$ parameters, mapping an input sequence of length $T$ to a single output, establishing an upper bound of $O(L W \log (T W))$ and a nearly matching lower bound of $\Omega(L W \log (T W / L))$.

arXiv Machine Learning
Aug 11

How Many Different Outputs Can a Transformer Generate?

arXiv:2605. 22223v2 Announce Type: replace Abstract: We study how we can leverage only a handful of characteristics of a transformer's architecture to closely predict the number of different sequences it can output, both qualitatively and quantitatively.

By Maxime Meyer, Mario Michelessa, Caroline Chaux, Vincent Y. F. Tan
arXiv Machine Learning
Jun 2

Length Generalization Bounds for Transformers

arXiv:2603. 02238v2 Announce Type: replace Abstract: Length generalization is a key property of a learning algorithm that enables it to make correct predictions on inputs of any length, given finite training data.

By Andy Yang, Pascal Bergstr\"a{\ss}er, Georg Zetzsche, David Chiang, Anthony W. Lin
arXiv AI
Jun 11

The Power of Test-Time Training for Approximate Sampling

arXiv:2606. 11437v1 Announce Type: cross Abstract: Efficiently sampling from a complex probability distribution is a fundamental problem which has become increasingly pertinent in recent years with the rise of generative AI, as sophisticated sampling procedures from LLMs have been proposed to solve challenging reasoning problems.

By Noah Golowich, Ankur Moitra, Dhruv Rohatgi
arXiv Machine Learning
Jul 9

The Optimal Sample Complexity of Learning Autoregressive Chain-of-Thought

arXiv:2607. 07423v1 Announce Type: new Abstract: We prove that, in the realizable PAC setting, the sample complexity of exact-trace learning for full autoregressive Chain-of-Thought traces is upper bounded by the standard multiclass rate of the local next-token class, where this rate is governed by the Daniely--Shalev-Shwartz dimension.

By Zhiyuan Li