Etale Cohomology

Tsimerman's notes

Some version of Poincare duality—perhaps something about perfect intersection pairings useful for extracting the intersection of diagonal $\Delta$ with the graph $\Gamma$ of a morphism—is apparently used to prove the Grothendieck–Lefschetz trace (fixed point) formula. Reference: Frietag–Kiehl.

Benson Farb, Representation Stability