English

Regularity vs. constructive complete (co)distributivity

Category Theory 2018-05-31 v2

Abstract

It is well known that a relation φ\varphi between sets is regular if, and only if, Kφ\mathcal{K}\varphi is completely distributive (cd), where Kφ\mathcal{K}\varphi is the complete lattice consisting of fixed points of the Kan adjunction induced by φ\varphi. For a small quantaloid Q\mathcal{Q}, we investigate the Q\mathcal{Q}-enriched version of this classical result, i.e., the regularity of Q\mathcal{Q}-distributors versus the constructive complete distributivity (ccd) of Q\mathcal{Q}-categories, and prove that "the dual of Kφ\mathcal{K}\varphi is (ccd)     \implies φ\varphi is regular     \implies Kφ\mathcal{K}\varphi is (ccd)" for any Q\mathcal{Q}-distributor φ\varphi. Although the converse implications do not hold in general, in the case that Q\mathcal{Q} is a commutative integral quantale, we show that these three statements are equivalent for any φ\varphi if, and only if, Q\mathcal{Q} is a Girard quantale.

Cite

@article{arxiv.1606.08930,
  title  = {Regularity vs. constructive complete (co)distributivity},
  author = {Hongliang Lai and Lili Shen},
  journal= {arXiv preprint arXiv:1606.08930},
  year   = {2018}
}

Comments

31 pages, final version

R2 v1 2026-06-22T14:37:46.257Z