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51 votes
5 answers
9k views

Fundamental group as topological group

Background Let $(X,x)$ be a pointed topological space. Then the fundamental group $\pi_1(X,x)$ becomes a topological space: Endow the set of maps $S^1 \to X$ with the compact-open topology, endow the ...
Martin Brandenburg's user avatar
36 votes
4 answers
5k views

Compact open topology on $\mathrm{Homeo}(X)$

Let $X$ and $Y$ be topological spaces. Define the compact open topology on the set $\mathrm{M}(X,Y)$ of continuous maps from $X$ to $Y$ via the subbase $[K,O]$ of all maps $f:X\rightarrow Y$ s.t. $f(K)...
Olivier Bégassat's user avatar
10 votes
2 answers
451 views

Group of surface homeomorphisms is locally path-connected

I think the following is true and I need a reference for the proof. (Given a closed surface $S$, i.e. a compact 2-dimensional topological manifold (without boundary), we endow $S$ with a distance ...
Arnaud Chéritat's user avatar
4 votes
0 answers
147 views

Does the self-homeomorphism group of a finite CW complex have CW homotopy type?

Let $X$ be a finite CW complex and form the group $\mathcal{H}(X)$ of self-homeomorphisms $X\xrightarrow{\cong}X$, furnishing it with the compact-open topology. Under the assumptions on our space $\...
Tyrone's user avatar
  • 5,596
4 votes
0 answers
133 views

Equivalence of Flat Fiber Bundles vs Equivalence of Group Actions on the Fiber

Let's consider all flat fiber bundles with base space $B$ and fiber $F$, where $B$ and $F$ are compact and at least CW-complexes. (perhaps even topological/smooth manifolds if that helps) All those ...
ort96's user avatar
  • 404
3 votes
1 answer
142 views

What's the topology on the mapping space $Map_H(G, Y)$ when $G$ is not finite

When $G$ is a finite group and $H$ a closed subgroup of it, the sets of right cosets $H\backslash G$ has the discrete topology on it. Let $Y$ be a $H-$space. We have the $G-$homeomorphism \begin{...
Megan's user avatar
  • 1,040
1 vote
1 answer
190 views

Approximations by compact sub-spaces

Suppose $X$ is a Hausdorff (I'm happy to also assume "non compact") topological space that can be written as the topological direct limit $$\varinjlim_{a\in J} K_a$$ for $J$ a directed set ...
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