If a K3 surface is a fiber of a flat projective morphisms over a connected noetherian scheme over the complex number field,then any smooth connected fiber is also a K3 surface.Observing this,Professor Nam-Hoon Lee ask...If a K3 surface is a fiber of a flat projective morphisms over a connected noetherian scheme over the complex number field,then any smooth connected fiber is also a K3 surface.Observing this,Professor Nam-Hoon Lee asked if the same is true for higher dimensional Calabi-Yau fibers.We shall give an explicit negative answer to his question in each dimension greater than or equal to three as well as a proof of his initial observation.展开更多
文摘If a K3 surface is a fiber of a flat projective morphisms over a connected noetherian scheme over the complex number field,then any smooth connected fiber is also a K3 surface.Observing this,Professor Nam-Hoon Lee asked if the same is true for higher dimensional Calabi-Yau fibers.We shall give an explicit negative answer to his question in each dimension greater than or equal to three as well as a proof of his initial observation.