Clarification on hilbert_distance module #9

Thanks for providing the Python wrapper for RIVET. I have recently started using your hilbert_distance module in my work and would appreciate some clarification.

Could you please point me to a paper or resource that describes the Hilbert distance in the context of multiparameter persistence? I couldn't find anything online or in the papers provided in the RIVET documentation. In the notebook, you mention that the Hilbert distance is defined as the "L2 distance on Hilbert functions of the persistence modules," but I find that this is not immediately clear from the implementation.

Thanks for your help!