By some analogy, the integral and differential can be extend to factorial differintegral, see <https://en.wikipedia.org/wiki/Differintegral>


My question is, what is the he geometry interpretation of fractional differintegral?



what is the geometry interpretation of fractional differintegral?
I recommend you [I.Podlubny Geometric and Physical Interpretation of Fractional Integration and Fractional Differentiation](https://arxiv.org/abs/math/0110241)


