activity
20232025
most citedWhat Formal Languages Can Transformers Express? A Survey

22 citations · 24 across the 5 of their papers we have counts for

collaborators

6 papers

cs.CL2025

Knee-Deep in C-RASP: A Transformer Depth Hierarchy

Andy Yang, Michaël Cadilhac, David Chiang

It has been observed that transformers with greater depth (that is, more layers) have more capabilities, but can we establish formally which capabilities are gained? We answer this…

cs.LG2024

Simulating Hard Attention Using Soft Attention

Andy Yang, Lena Strobl, David Chiang +1

We study conditions under which transformers using soft attention can simulate hard attention, that is, effectively focus all attention on a subset of positions. First, we examine…

cs.LO2024

Counting Like Transformers: Compiling Temporal Counting Logic Into Softmax Transformers

Andy Yang, David Chiang

Deriving formal bounds on the expressivity of transformers, as well as studying transformers that are constructed to implement known algorithms, are both effective methods for bett…

cs.FL2024★ 1 cited

Transformers as Transducers

Lena Strobl, Dana Angluin, David Chiang +2

We study the sequence-to-sequence mapping capacity of transformers by relating them to finite transducers, and find that they can express surprisingly large classes of transduction…

cs.LG2023★ 22 cited

What Formal Languages Can Transformers Express? A Survey

Lena Strobl, William Merrill, Gail Weiss +2

As transformers have gained prominence in natural language processing, some researchers have investigated theoretically what problems they can and cannot solve, by treating problem…

cs.FL2023★ 1 cited

Masked Hard-Attention Transformers Recognize Exactly the Star-Free Languages

Andy Yang, David Chiang, Dana Angluin

The expressive power of transformers over inputs of unbounded size can be studied through their ability to recognize classes of formal languages. In this paper, we establish exact…