For instance,if $\int f=\frac{1}{a}e^{ax}$ is regard as integral in one time,we use notation $T(1)\int f=\frac{1}{a}e^{ax}$,we may extend it to fractional ,real,or complex time in such a way:$$T(\alpha)\int f=\frac{1}{a^{\alpha}}e^{ax},\alpha \in N,Z,Q,R,or C$$.
We even may extend $\alpha$ to a more general field than C.
First question :with what class of function f can the intergral be extended in such a way? every integralable one?
Second question:what is the application of such extension in math?Anyone gives any example?
Third question:can we explain such extension or operation by geometry as usual integral?How should we explain such extension or operation by geometry?It can not intepreted in geometry?
Fourth question:what are the more general extension of such operation than C?

