| 概要 | Donaldson-Thomas (DT) invariant is a counting invariant
of stable sheaves on a Calabi-Yau 3-fold, and the rank
one theory counts curve on it. On the other hand by
developing DT theory on the derived category of coherent
sheaves, several important properties have been proved
recently, e.g. DT/PT correspondence, rationality conjecture.
In this talk, I will give a survey on the recent development
in this research field. |