- Derivatives at Boundary Points
- Abian, Alexander ; Wilson, James A. ;
- Kyungpook mathematical journal, volume 38, issue 2, 1998, Pages 359~359
Abstract
In this paper theorems are proved concerning the existence of derivatives of real and complex functions at boundary points (one-sided derivatives in the case of real-valued functions of a real variable). A real variable theorem and a complex variable analog are proved below. A point of interest here is that the complex function case is quite easily proved using a method of proof essentially different from that of the real function case, and to prove both theorems by the same method, while possible, requires more insightful argument. See Remark below.