Proving isometries of the plane are bijective
109643
Prove that every isometry on $\mathbb{R}^2$ is bijective
95513
Proving $W$ is a subspace of $P_{2}$
118595
Proving that a set is countable by finding a bijection
130363
Prove composition of two surjections is surjection
40490
Birational isomorphism $\mathbb{P}^n\times \mathbb{P}^m\to \mathbb{P}^{n+m}$
96202
Prove composition of bijections is bijection
95086
Homeomorphism is bijective
41846
$(\mathbb{R}^n,\|\cdot\|_{p})$ is isometrically isomorphic to $(\mathbb{R}^n,\|\cdot\|_{q})$ iff $p=q,$
41359
Constructing a bijection
119139
Show that antipodal points remain antipodal under any isometry of $S^2$
146356
To prove two sets are isomorphic is it sufficient to find 2 injections or 2 surjections?
14277
Proving $f(x)=x\cdot |x|$ is a bijection
131881
Show that the roots of P' lie in the same half plane as the roots of P
71975
Showing that an Isometry on the Euclidean Plane fixing the origin is Linear
45179
When does the isomorphism $G\simeq \ker(\phi)\times \operatorname{im}(\phi)$? hold?
50731
Isometries of the sphere $\mathbb{S}^{n}$
72642
Continuous bijection from $(a,b) \to S^1$?