Geometric construction of generators of CoHA of doubled quiver
  Let $Q$ be the doubled of a quiver. According to Efimov, Kontsevich and Soibelman, the cohomological Hall algebra (CoHA) associated to $Q$ is a free super-commutative algebra. In this short note, we confirm a conjecture of Hausel which gives a geometric realisation of the generators of the CoHA. 
Zongbin Chen
math.AG