very interesting... I can't quite grok what is going on, but referencing the paper gives a great starting point. Thank you. In particular the notion of a Dens

very interesting... I can't quite grok what is going on, but referencing the paper gives a great starting point. Thank you. In particular the notion of a DensitySum seems novel and worth exploring. (for others, http://www.ofey.me/papers/cetd-sigir11.pdf http://www.ofey.me/papers/cetd-sigir11.pdf)