| 概要 | We'll think about birational maps coming from polarization
change (or wall-crossing) of moduli schemes of sheaves on
a surface X.
(i) When X has positive Kodaira dimension, these birational
maps concern with flips, minimal models, etc.
(ii) When Kod(X)=0, some finiteness holds for the family
of biratinal moduli schemes induced by polarization change.
Also some examples concerning extremal rays and faces of moduli
of sheaves will be mentioned. |