The congruence biframe as a quasi-uniform bicompletion
arXiv:1902.06340 · doi:10.1016/j.topol.2019.106968
Abstract
Künzi and Ferrario have shown that a space is sober if and only if it is bicomplete in the well-monotone quasi-uniformity. We prove a pointfree version of this result: a strictly zero-dimensional biframe is a congruence biframe if and only if it is bicomplete in the same quasi-uniformity. As a corollary we obtain a new proof of a result of Plewe that a congruence frame is ultraparacompact. The main result makes use of a new construction of the bicompletion of a quasi-uniform biframe as a quotient of the Samuel compactification.
12 pages, 0 figures. To be published in Topology and its Applications