====== Forman curvature ======

  * [[https://arxiv.org/pdf/1603.00386.pdf|Forman curvature]]
  * https://arxiv.org/pdf/1605.04662.pdf
  * http://www.mdpi.com/2075-1680/5/4/26/pdf
  * https://web.math.princeton.edu/~mw25/assets/files/WeberSaucanJost_2016a.pdf
  * https://www.mis.mpg.de/jjost/publications/graphs.html