How does one deal with finding the branches of a multi-valued function of a complex variable that is the sum of two multi-valued functions, something like the following:
$f(z) = \sqrt{z} + \sqrt{1 - z}$,
$f(z) = \sqrt{z} + \sqrt{z - 1}$,
$f(z) = \sqrt{z} + \sqrt{z(z - 1)}$
$f(z) = \log(z - 1) + \sqrt{z}$?
In other words: how does one understand the algebra of branch cuts and branch points in general?