| 概要 | We study the locus of non-locally-free sheaves on the singular moduli space that O'Grady's six dimensional example of irreducible symplectic K\"ahler manifold is constructed from. This involves a quiver-variety-like description of the fiber of the morphism to Donaldson-Uhlenbeck compactification. Passing to the resolved symplectic moduli space, we determine the birational geometry of O'Grady's six dimensional example relative to Donaldson-Uhlenbeck compactification in an explicit way. |