A general framework for the faithful pointfree representation of T0-spaces (Preprint)

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Type: Preprint
National /International: International
Title: A general framework for the faithful pointfree representation of T0-spaces
Publication Date: 2026-06-27
Authors: - Rui Prezado
- Anna Laura Suarez
Abstract:

We introduce a general framework for studying natural contravariant adjunctions that refine the adjunction between frames and spaces so that the fixpoints are T0-spaces.
Our objects of study are spatializable \( \mathbf{Frm} \)-concrete categories, or SFC-categories. These consist of a faithful functor \( \mathcal O\colon\mathcal C\to \mathbf{Frm} \) equipped with an object \( 2_{\mathcal C}\in\mathcal C \), satisfying compatibility conditions that ensure that \( (2_{\mathcal C},\mathbb S) \) forms a dualizing object in the sense of Porst and Tholen, where \( \mathbb S \) denotes the Sierpiński space. 
Three important instances of pointfree T0 spaces present in the literature fit into this framework: strictly zero-dimensional biframes, MT-algebras, and Raney extensions.
We show SFC-categories are assembled in an ordered category -- a category enriched in preordered sets -- whose morphisms are suitable functors which preserve certain initial liftings. SFC-categories induce natural dual adjunctions, and morphisms between them will respectively induce suitable morphisms between these adjunctions.
Motivated by the characterization of sober spaces as maximal objects in the fibers of \( \Omega\colon \mathbf{Top}\to\mathbf{Frm}^{\mathbf {op}} \) , and of TD-spaces as the minimal ones, due to Banaschewski and Pultr, we study initial and terminal objects of fibers for an arbitrary SFC-category. We prove that the natural adjunction for fiber-initials has exactly the sober spaces as fixpoints, while for fiber-terminals contains at most TD-spaces, recovering their results of in a much more general setting.

Institution: arXiv:2606.28691
Online version: https://arxiv.org/abs/2606.28691
Download: Not available
 
© Centre for Mathematics, University of Coimbra, funded by
Science and Technology Foundation
Financiado total ou parcialmente pela FCT, Fundação para a Ciência e a Tecnologia, I.P., sob o Financiamento de:
UID/00324/2025 Projeto Estratégico com a referência DOI https://doi.org/10.54499/UID/00324/2025.
https://doi.org/10.54499/UID/PRR/00324/2025     UID/PRR/00324/2025   https://doi.org/10.54499/UID/PRR2/00324/2025   UID/PRR2/00324/2025
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