Could I just get a final clarification on XPX (ProximaX) being run on top of the current NEM blockchain?  Is XPX just a mosaic on the NEM public blockchain, or is ProximaX running indepentently on another public blockchain (inspired by NEM tech)?     I'm looking at adding to my investment in NEM(XEM), but need clarification on the PromimaX position.  I read the whitepaper.