Moduli of PT-semistable objects II

Understand

We generalise the techniques of semistable reduction for flat families of sheaves to the setting of the derived category $D^b(X)$ of coherent sheaves on a smooth projective three-fold $X$.

• Then we construct the moduli of PT-semistable objects in $D^b(X)$ as an Artin stack of finite type that is universally closed.
• In the absence of strictly semistable objects, we construct the moduli as a proper algebraic space of finite type.