Topological groups on the circle $S^1$
74383
How many group structures make $S^1$ a topological group?
135059
Prove that the unit circle, $S^1:=\{(x,y)\in \mathbb{R}^2: x^2+y^2=1\}$, Is a one-dimensional manifold
27652
metric on the Euclidean Group
24039
Fundamental Group of Punctured Plane
52556
Isomorphism of $S^1$.
119050
Fundamental group of $S^2$ with north and south pole identified
142577
Algebraic proof that a set generated by irrational rotations is dense in $S^1$.
154303
Degree $1$ map from torus to sphere
112407
Set of left cosets is a group
61262
Is $\cot(z)-\frac1z$ bounded on a given circle?
27629
How to prove that $S^{2n+1}/S^1$ is homeomorphic to $\mathbb CP^n$ under a given identification
129943
Torsion on $\pi_1(X)$, $X$ connected and open in $\mathbb{R}^n$
144548
topological structure on smooth manifolds
128301
Homeomorphism from square to unit circle
37635
Diffeomorphism group of the unit circle
34966
Is the product of closed subgroups in topological group closed?
130081
Show that $A_n$ is the kernel of a group homomorphism of $S_n \rightarrow \{−1,1\}$.