Define \(A \da \ts{\Re(z) > 0, \Im(z) > 0}\). Find a conformal equivalence \(\Delta \intersect A \to A\).
Solution
The composite of the following three maps is a conformal equivalence \(\Delta\intersect A\to A\).
The squaring map \(z\mapsto z^2\) sends \(\Delta\intersect A\) onto \(\DD \intersect \HH\).
The negated Joukowski map \(z\mapsto -{1\over 2}(z+\inverseof{z})\) sends \(\DD\intersect\HH\) onto \(\HH\).
The principal branch of \(z\mapsto z^{1\over 2}\) sends \(\HH\) onto the first quadrant \(A\).