ACL 2025long0 citations

Tokenisation is NP-Complete

Philip Whittington, Gregor Bachmann, Tiago Pimentel

Abstract

In this work, we prove the NP-completeness of two variants of tokenisation, defined here as the problem of compressing a dataset to at most 𝛿 symbols by either finding a vocabulary directly (_direct_ tokenisation), or selecting a sequence of merge operations (_bottom-up_ tokenisation).

BibTeX
@inproceedings{whittington-etal-2025-tokenisation,
    title = "Tokenisation is {NP}-Complete",
    author = "Whittington, Philip  and
      Bachmann, Gregor  and
      Pimentel, Tiago",
    editor = "Che, Wanxiang  and
      Nabende, Joyce  and
      Shutova, Ekaterina  and
      Pilehvar, Mohammad Taher",
    booktitle = "Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)",
    month = jul,
    year = "2025",
    address = "Vienna, Austria",
    publisher = "Association for Computational Linguistics",
    url = "https://aclanthology.org/2025.acl-long.1365/",
    doi = "10.18653/v1/2025.acl-long.1365",
    pages = "28133--28153",
    ISBN = "979-8-89176-251-0"
}