Endomorphisms of $\mathbb{H}$ that do not fix $\mathbb{R}$
46664
Is every endomorphism of the quaternion ring surjective?
88474
$\mathbb{A}^{2}$ not isomorphic to affine space minus the origin
19984
Example of topological spaces with continuous bijections that are not homotopy equivalent
127886
Artin's lemma and some morphisms.
98436
Finite order endomorphisms
126472
Surjective endomorphisms of uniserial modules
2348
Show that the sphere, S, and $\mathbb{R}^2$ is not homeomorphic
57468
Continuous homorphisms between topological groups.
97608
Showing a Ring of endomorphisms is isomorphic to a Ring
41872
Show that $\mathbb{R}^2$ is not homeomorphic to $\mathbb{R}^2 \setminus\{(0,0)\}$
45432
Showing that $f:(0,2\pi]\to S^1$ is not a homeomorphism
154142
Finding a specific basis for an endomorphism
65034
Are continuous self-bijections of connected spaces homeomorphisms?
132386
Show that $(\mathbb{Q}^*,\cdot)$ and $(\mathbb{R}^*,\cdot)$ aren't cyclic
27670
Group homomorphisms $\mathbb{Q}\to\mathbb{R}$
33140
Two non-homeomorphic spaces with continuous bijective functions in both directions
27757
$\mathbb{R}\to\mathbb{R}$ Diffeomorphism with special property