SCHEMATIC HARDER–NARASIMHAN STRATIFICATION
SCHEMATIC HARDER–NARASIMHAN STRATIFICATION
For any flat family of pure-dimensional coherent sheaves on a family of projective schemes, the Harder–Narasimhan type (in the sense of Gieseker semistability) of its restriction to each fiber is known to vary semicontinuously on the parameter scheme of the family. This defines a stratification of the parameter scheme by …