Let be $M= \left\lbrace (x,y,z,w) \in \mathbb{R}^4 \mid x^2+y^2- z^2-w^2 = 1 \right\rbrace$.
I have proved that $M$ is a embedded submanifold of $\mathbb{R}^4 $ of dimension $3$.
I have now to prove that $M$ is diffeomorphic to $\mathbb{R}^2 \times S^1 $.
Can someone give me an hint to find a diffeomorphism?
Thanks a lot!
HINT: Can you write down a diffeomorphism $$S^1\times\Bbb R\to \{(x,y,z)\in\Bbb R^3: x^2+y^2-z^2=1\}?$$