I have this problems
- Proof that the ball $B_1{(0,0)}$ can be embedded in Moore plane (Niemytzki plane)
- Proof that $({\mathbb R}^3; \textrm{usual topology})$ can be embedded in Moore plane (Niemytzki plane)
- Proof that $({\mathbb R}; \textrm{usual topology})$ can be embedded in Moore plane (Niemytzki plane)
For the second I dont know if the function $h(x)=\left(x,\arctan(x)+ \frac{\pi}{2}\right)$ is right.
Thanks