Axioms:
- $P_1$:
Existence of Parallel
\[
\forall r \in \mathcal{R},
~~
\forall P \notin r:
\exists s:
r \parallel s
\wedge
P \in s
\]
- $P_2$:
Unicity of Parallel
\[
\forall r \in \mathcal{R},
~~
\forall P \notin r:
\exists ! s:
r \parallel s
\exists
P \in s
\]
Humanity trying to prove this for 2000 years...