Principal branch

In mathematics, a principal branch is a function which selects one branch ('slice') of a multi-valued function. Most often, this applies to functions defined on the complex plane. In mathematics, a principal branch is a function which selects one branch ('slice') of a multi-valued function. Most often, this applies to functions defined on the complex plane. Principal branches are used in the definition of many inverse trigonometric functions, such as the selection either to define that