English

A Cartesian Promonoidal Kernel on $\Delta$ and a Hadamard Contraction of $\Delta^n$

Category Theory 2025-10-31 v2 Algebraic Topology

Abstract

We exhibit a symmetric promonoidal kernel on the simplex category Δ\Delta with Cartesian unit, yielding on representable functors a Hadamard natural transformation Δp×ΔqΔpq\Delta^p\times\Delta^q\to\Delta^{pq} based on pointwise multiplication of nondecreasing maps. Specializing to q=1q=1 yields a simplicial homotopy contracting Δn\Delta^n to its 00-vertex. The contraction is classical; the promonoidal presentation and induced Hadamard map appear not to be recorded.

Keywords

Cite

@article{arxiv.2510.19104,
  title  = {A Cartesian Promonoidal Kernel on $\Delta$ and a Hadamard Contraction of $\Delta^n$},
  author = {Florian Lengyel},
  journal= {arXiv preprint arXiv:2510.19104},
  year   = {2025}
}

Comments

8 pages; short note; added reference to GarnerStreet2015