Topology and its Applications ( IF 0.6 ) Pub Date : 2021-06-01 , DOI: 10.1016/j.topol.2021.107740 Angel Calderón , Iván Sánchez
We study the Raĭkov completion of a paratopological group G defined by Banakh-Ravsky in 2020. This permits to Banakh and Tkachenko introduce the notion of -semicompletion, where is a class of continuous homomorphisms of paratopological groups. We show that the product of -semicompletions is a -semicompletion for the product of arbitrary paratopological groups. In particular, if we consider the class of all continuous homomorphisms between paratopological groups, we obtain that . We also study the interaction between -semicompletions of a paratopological group G and the -semicompletions of subgroups of G.
We prove that if G is a paratopological group, then every -semicompletion of G is . We show that if G is first-countable (second-countable), then every -semicompletion of G is first-countable (second-countable). Therefore, if G is metrizable separable, then every -semicompletion of G is metrizable separable as well.
中文翻译:
副拓扑群半完备的一些性质
我们研究 Raĭkov 完成 由 Banakh-Ravsky 在 2020 年定义的超拓扑群G。这允许 Banakh 和 Tkachenko 引入概念-半完成,其中是一类互补拓扑群的连续同态。我们证明了产品-半完成是一个 - 任意副拓扑群的产物的半完成。特别地,如果我们考虑类 对所有互补拓扑群之间的连续同态,我们得到 . 我们还研究了- 一个超拓扑群G和- G的子群的半完成。
我们证明如果G是一个 超拓扑群,那么每个 的-semicompletion ģ是. 我们证明如果G是第一可数(第二可数),那么每个的-semicompletion ģ是第一可数(第二可数)。因此,如果G是可度量可分的,那么每的-semicompletion ģ是度量化可分离为好。