English

You Wouldn't Permutahedron

Category Theory 2024-08-02 v2 Combinatorics

Abstract

We develop formulas that define permutahedral commutation coherence relations of all orders. To illustrate the result geometrically, we begin by defining a rigid transformation of the (n+1)(n+1)-permutahedron into a nn-cube of dimensions 1×2××n1 \times 2 \times \cdots \times n. With a fictitious assumption, we 'define' the corresponding coherence relations 'up to associativity' as an instance of a semi-simplicial type in the language of Displayed Type Theory. This is not a formal result in type theory, but we expect this to translate into one as soon as the problem of defining associahedral coherences is solved in a type theory with semi-simplicial types. On the other hand, this not-strictly-well-typed definition may be used to produce well-typed formulas in a restricted setting.

Keywords

Cite

@article{arxiv.2407.10891,
  title  = {You Wouldn't Permutahedron},
  author = {Astra Kolomatskaia},
  journal= {arXiv preprint arXiv:2407.10891},
  year   = {2024}
}

Comments

20 pages, 1 figure, v2: new appendix on the theory and implementation of dTT

R2 v1 2026-06-28T17:41:34.845Z