Fairest Edge Usage and Minimum Expected Overlap

Formalization of "Fairest Edge Usage and Minimum Expected Overlap for Random Spanning Trees" (Albin, Clemens, Hoare, Poggi-Corradini, Sit, Tymochko, 2021), https://doi.org/10.1016/j.disc.2020.112282

Placeholder: definitions from Section 1 (random spanning trees, MEO, FEU) to come.