Schwarz reflection principle
For a region define (where is the complex conjugate of ). If is a symmetric region, that is , then we define , and .
Theorem.
Let be a region such that and suppose that is a continuous functions that is analytic on and further that is real for (that is for real ), then there is an analytic function such that for .
That is you can “reflect” an analytic function across the real axis. Note that by composing with various conformal mappings you could generalize the above to reflection across an analytic curve. So loosely stated, the theorem says that if an analytic function is defined in a region with some “nice” boundary and the function behaves “nice” on this boundary, then we can extend the function to a larger domain. Let us make this statement precise with the following generalization.
Theorem.
Let be regions and let and be free analytic boundary arcs in and . Suppose that is a continuous function that is analytic on , and , then for any compact set , has an analytic continuation to an open set containing .
References
- 1 John B. Conway. . Springer-Verlag, New York, New York, 1978.
- 2 John B. Conway. . Springer-Verlag, New York, New York, 1995.
Title | Schwarz reflection principle |
---|---|
Canonical name | SchwarzReflectionPrinciple |
Date of creation | 2013-03-22 14:17:58 |
Last modified on | 2013-03-22 14:17:58 |
Owner | jirka (4157) |
Last modified by | jirka (4157) |
Numerical id | 7 |
Author | jirka (4157) |
Entry type | Theorem |
Classification | msc 30C35 |
Synonym | Schwarz reflection theorem |
Synonym | reflection principle |
Defines | symmetric region |