Defining $\mathbb{C}$ without defining $\mathbb{R}$
139514
Can we construct $\Bbb C$ without first identifying $\Bbb R$?
73248
Prove that $\mathbb{R^*}$, the set of all real numbers except $0$, is not a cyclic group
109610
Is $\mathbb{R}[X]/(P)$ isomorphic to $\mathbb C$ for every irreducible polynomial $P$ of degree $2?$
1117
Is there a bijection between $(0,1)$ and $\mathbb{R}$ that preserves rationality?
3902
Does $k+\aleph_0=\mathfrak{c}$ imply $k=\mathfrak{c}$ without the Axiom of Choice?
2575
Showing that $\mathbb{R}$ is connected
116630
Antiderivative $1/z$ on $\mathbb C$
70576
Elementary proof that $\mathbb{R}^n$ is not homeomorphic to $\mathbb{R}^m$
105772
Definition of $\mathbb{R}^\infty$
100919
Examples of non-measurable sets in $\mathbb{R}$
53335
Why isn't $\mathbb{C}[x,y,z]/(xz-y)$ a flat $\mathbb{C}[x,y]$-module
128917
Inner Product on $\mathbb{R}$ and on $\mathbb{C}$
143354
Prove that there exists $c\in\mathbb{R}$ such that $f'(c)=f(c)$
110944
Proving that $AB-BA=cI$ for nontrivial $c \in \mathbb{C}$
135441
When is $\mathbb{Z}[\alpha]$ dense in $\mathbb{C}$?
69166
Cardinality of $\mathbb{R}$ and $\mathbb{R}^2$
5098
Theorem without numbering