Let $S$ be a birationally ruled surface. We show that the moduli schemes$M_S(r,c_1,c_2)$ of semistable sheaves on $S$ of rank $r$ and Chern classes$c_1$ and $c_2$ are irreducible for all $(r,c_1,c_2)$ provided the polarizationof $S$ used satisfies a simple numerical condition. This is accomplished byproving that the stacks of prioritary sheaves on $S$ of fixed rank and Chernclasses are smooth and irreducible.
展开▼
机译：令$ S $为双平分面。我们显示了在等级$ r $的$ S $和陈类$ c_1 $和$ c_2 $上的半稳定滑轮的模数方案$ M_S（r，c_1，c_2）$对于所有$（r，c_1，c_2）都是不可约的只要所使用的$ S $的极化满足一个简单的数值条件，即可使用$。这是通过证明固定等级和Chernclass的$ S $上优先轮的堆叠是平滑且不可约的来实现的。
展开▼
