On Fano 4-folds of index 1 and homogeneous vector bundles over Grassmannians.
On hypersurface quotient singularities of dimension 4.
On numerically effective log canonical divisors.
On representation varieties of Artin groups, projective arrangements and the fundamental groups of smooth complex algebraic varieties
On the (-1)-curve conjecture of Friedmann and Morgan.
On two conjectures of Hartshorne's.