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Let $f,g$ be a pair of univalent functions on a proper subdomain $\Omega$ of $\mathbb C$. Does their sum $f+g$ necessarily omit any complex value?
Similarly, can all holomorphic function be written as sums of univalent functions?
$\begingroup$No to both in as simple domain as the unit disk. 1) $(1-z)^{-2}-(1+z)^{-2}$ 2) Univalent functions cannot grow too fast near the boundary.$\endgroup$
$z$
and$1/z$
on${\bf C} - \{0\}$
. $\endgroup$