English

Adjoint functor theorems for lax-idempotent pseudomonads

Category Theory 2025-10-16 v2

Abstract

For each pair of lax-idempotent pseudomonads RR and II, for which II is locally fully faithful and RR distributes over II, we establish an adjoint functor theorem, relating RR-cocontinuity to adjointness relative to II. This provides a new perspective on the nature of adjoint functor theorems, which may be seen as methods to decompose adjointness into cocontinuity and relative adjointness. As special cases, we recover variants of the adjoint functor theorem of Freyd, the multiadjoint functor theorem of Diers, and the pluriadjoint functor theorem of Solian--Viswanathan, as well as the adjoint functor theorems for locally presentable categories. More generally, we recover enriched Φ\Phi-adjoint functor theorems for weakly sound classes of weight Φ\Phi.

Keywords

Cite

@article{arxiv.2306.10389,
  title  = {Adjoint functor theorems for lax-idempotent pseudomonads},
  author = {Nathanael Arkor and Ivan Di Liberti and Fosco Loregian},
  journal= {arXiv preprint arXiv:2306.10389},
  year   = {2025}
}

Comments

14 pages; v2: new references and examples

R2 v1 2026-06-28T11:07:59.254Z