Using the Grünwald-Letnikov definition of fractional derivative for complex-valued functions, can there be complex function $f(z)$ over all plane, that is not holomorphic but there is $r \in (0,1)$ s.t. $r$-th Grünwald-Letnikov derivative of $f(z)$ exists for all $z$?
$\begingroup$
$\endgroup$
Add a comment
|