04/09/2023, 05:01 PM
(04/08/2023, 10:41 PM)JmsNxn Wrote: You can also see Kneser as the unique function \(f\) such that:
\[
|f'(z+1)| =|e^{f(z)}|\\
\]
if we assume that \(|f'(z)| =1\).........
This is explained through basic level set calculus....
What ?!?
That seems like a universal tetration property for complex continu ( not even analytic required ) solutions.
f(z+1) = exp(f(z))
so by the chain rule
f ' (z+1) = exp'(f(z)) f'(z) = exp(f(z)) * a = exp(f(z) + ln(a))
so if f ' (z) = a and a is a root of unity :
| f ' (z+1) | = | exp'(f(z)) f'(z) | = | exp(f(z)) * a | = | exp(f(z) + ln(a)) | = |a| | exp(f(z)) | = | exp(f(z)) |
QED
All we need is some vague notion of differentiable to define some at least a weak derivative consistant over the domains and ranges considered.
regards
tommy1729

