一句话:把 Vickers 的 localic 完备化从广义度量空间推广到广义一致空间,并证明其与 Cauchy 滤子完备化一致。
论文将 Vickers 的广义度量空间 localic 完备化推广到广义一致空间(gus)。作者在构造性集合论 CZF 加 Regular Extension Axiom 中工作,必要时用可数选择,把对称 gus 的广义一致结构提升为无点结构,并在形式点上得到与 Cauchy 滤子标准完备化一致的完备广义一致结构。进一步,localic 完备化给出从局部紧一致空间范畴到 overt、局部紧、完全正则形式拓扑范畴的全忠实函子;论文还给出局部紧一致空间覆盖的基本刻画,简化度量空间情形,并证明对称 gus 的 localic 完备化等价于其关联一致形式拓扑的无点完备化。
We extend the notion of localic completion of generalised metric spaces by Steven Vickers to the setting of generalised uniform spaces. A generalised uniform space (gus) is a set X equipped with a family of generalised metrics on X, where a generalised metric on X is a map from the product of X to the upper reals satisfying zero self-distance law and triangle inequality. For a symmetric generalised uniform space, the localic completion lifts its generalised uniform structure to a point-free generalised uniform structure. This point-free structure induces a complete generalised uniform structure on the set of formal points of the localic completion that gives the standard completion of the original gus with Cauchy filters. We extend the localic completion to a full and faithful functor from the category of locally compact uniform spaces into that of overt locally compact completely regular formal topologies. Moreover, we give an elementary characterisation of the cover of the localic completion of a locally compact uniform space that simplifies the existing characterisation for metric spaces. These results generalise the corresponding results for metric spaces by Erik Palmgren. Furthermore, we show that the localic completion of a symmetric gus is equivalent to the point-free completion of the uniform formal topology associated with the gus. We work in Aczel's constructive set theory CZF with the Regular Extension Axiom. Some of our results also require Countable Choice.Comment: 39 pages