94 research outputs found
Small loop spaces and covering theory of non-homotopically Hausdorff spaces
In this paper we devote to spaces that are not homotopically hausdorff and
study their covering spaces. We introduce the notion of small covering and
prove that every small covering of is the universal covering in categorical
sense. Also, we introduce the notion of semi-locally small loop space which is
the necessary and sufficient condition for existence of universal cover for
non-homotopically hausdorff spaces, equivalently existence of small covering
spaces. Also, we prove that for semi-locally small loop spaces, is a small
loop space if and only if every cover of is trivial if and only if
is an indiscrete topological group.Comment: 7 page
Spanier spaces and covering theory of non-homotopically path Hausdorff spaces
H. Fischer et al. (Topology and its Application, 158 (2011) 397-408.)
introduced the Spanier group of a based space which is denoted by
\psp. By a Spanier space we mean a space such that \psp=\pi_1(X,x), for
every . In this paper, first we give an example of Spanier spaces. Then
we study the influence of the Spanier group on covering theory and introduce
Spanier coverings which are universal coverings in the categorical sense.
Second, we give a necessary and sufficient condition for the existence of
Spanier coverings for non-homotopically path Hausdorff spaces. Finally, we
study the topological properties of Spanier groups and find out a criteria for
the Hausdorffness of topological fundamental groups.Comment: 14 pages, 2 figures. arXiv admin note: text overlap with
arXiv:1102.0993 by other author
On locally 1-connectedness of quotient spaces and its applications to fundamental groups
Let be a locally 1-connected metric space and be
connected, locally path connected and compact pairwise disjoint subspaces of
. In this paper, we show that the quotient space
obtained from by collapsing each of the sets 's to a point, is also
locally 1-connected. Moreover, we prove that the induced continuous
homomorphism of quasitopological fundamental groups is surjective. Finally, we
give some applications to find out some properties of the fundamental group of
the quotient space .Comment: 11 page
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