摘要
设X是n维非奇异射影簇,L是X上的丰富线丛,KX是X的典范丛,f:X→Y是以为KX+mL支撑除子的收缩态射(m≥1),F是f的任一纤维.文中证明了,如果dimF=m,那么F同构于m维射影空间Pm或者m+1维射影空间Pm+1中的超二次曲面Qm.
Letbe a nonsingular projective variety of dimension, be an ample line bundle overand be the canonical bundle over. Letbe the nef contraction fromtowith supporting divisor for some, be any generic fiber of. if, dimF=m then F is isomorphic to projective space or hyperquadrie in.
出处
《广东技术师范学院学报》
2014年第7期10-11,15,共3页
Journal of Guangdong Polytechnic Normal University
关键词
射影簇
丰富线丛
收缩态射
纤维
projective variety
ample line bundle
contraction morphism
fiber