期刊名称：International Journal of Mathematics and Mathematical Sciences
印刷版ISSN：0161-1712
电子版ISSN：1687-0425
出版年度：2001
卷号：28
DOI：10.1155/S016117120100727X
出版社：Hindawi Publishing Corporation
摘要：Montgomery and Zippin saied that a group is approximated by Lie
groups if every neighborhood of the identity contains an
invariant subgroup H such that G/H is topologically
isomorphic to a Lie group. Bagley, Wu, and Yang gave a similar
definition, which they called a pro-Lie group. Covington extended
this concept to a protopological group. Covington showed that
protopological groups possess many of the characteristics of
topological groups. In particular, Covington showed that in a
special case, the product of protopological groups is a
protopological group. In this note, we give a
characterization theorem for protopological groups and use it to
generalize her result about products to the category of all
protopological groups.
