The Weyl extension algebra of $GL_2(\bar{\mathbb{F}}_p)$
  We compute the Yoneda extension algebra of the collection of Weyl modules for $GL_2$ over an algebraically closed field of positive characteristic p by developing a theory of generalised Koszul duality for certain 2-functors, one of which controls the rational representation theory of $GL_2$ over such a field. 
Vanessa Miemietz and Will Turner
math.RT