Monodromy theorem
Statement
Suppose is an open subset and are two smooth curves from to that are smoothly homotopic. Suppose is an open subset contained inside and is a holomorphic function.
Let denote the intermediate curves for the homotopy between and . Then, suppose the following is true:
For every , we can extend to a holomorphic function on an open subset containing
Then any two s agree on the overlap and thus, all the values are equal.