Is the structure $(\mathbb{R}, +, *)$ rigid?
30817
Is an automorphism of the field of real numbers the identity map?
93263
Can contractible subspace be ignored/collapsed when computing $\pi_n$ or $H_n$?
127719
Is the matrix $R$ in the $QR$ decomposition unique?
82474
Isometries of $\mathbb{R}^n$
41846
$(\mathbb{R}^n,\|\cdot\|_{p})$ is isometrically isomorphic to $(\mathbb{R}^n,\|\cdot\|_{q})$ iff $p=q,$
138653
Is $\mathbb{R}$ a subspace of $\mathbb{R}^2$?
61226
Group Structure on $\Bbb R$
66272
Is there a common notion of $\mathbb{R}^n$, for non-integer $n$?
90475
Coordinate-free proof of $\operatorname{Tr}(AB)=\operatorname{Tr}(BA)$?
1117
Is there a bijection between $(0,1)$ and $\mathbb{R}$ that preserves rationality?
88474
$\mathbb{A}^{2}$ not isomorphic to affine space minus the origin
116168
Is $e^x$ the only isomorphism between the groups $(\mathbb{R},+)$ and $(\mathbb{R}_{> 0},*)$?
70576
Elementary proof that $\mathbb{R}^n$ is not homeomorphic to $\mathbb{R}^m$
37222
What is the precise definition of a rigid shape?
79727
Direct proof of non-flatness
118288
Complex structure on $\mathbb S^1 \times \mathbb S^3$
118622
Local diffeomorphism from $\mathbb R^2$ onto $S^2$