Editing Multivalued function (section)

== Branch points ==
{{Main articles|Branch point}}
Multivalued functions of a complex variable have [[branch point]]s. For example, for the ''n''th root and logarithm functions, 0 is a branch point; for the arctangent function, the imaginary units ''i'' and &minus;''i'' are branch points. Using the branch points, these functions may be redefined to be single-valued functions, by restricting the range. A suitable interval may be found through use of a [[branch cut]], a kind of curve that connects pairs of branch points, thus reducing the multilayered [[Riemann surface]] of the function to a single layer. As in the case with real functions, the restricted range may be called the ''principal branch'' of the function.