0
$\begingroup$

Prove that the Hopf map $\phi:S^3 \to S^2$ with $\phi(x,y)=(2x\bar y,|x|^2-|y|^2)$ is a submersion.

I need to show for that map rank $d\phi=2$. But how can I find partial derivative of $d(2x\bar y)/dy$. I'm stuck. Thank you.

1 Answers 1

1

$$ K = x \bar{y} = (a + bi) (u - vi) = au + bv + (bu - av) i $$

$$ \partial K / \partial u = a + bi \\ \partial K / \partial v = b - ai \\ $$

It may be easiest to write out a $4 \times 4$ real determinant rather than a $2 \times 2$ complex one.