On a remark by Y. Namikawa
arXiv:0807.4104
Abstract
The aim of the present paper is on the one hand to produce examples supporting the conclusion of Y. Namikawa in Remark 2.8 of \cite{N} and improving considerations of Example 1.11 of the same paper. On the other hand, it is intended to give a geometric interpretation of the rigidity properties of some trees of exceptional rational curves, as observed by Namikawa, which can be obtained by factorizing small resolutions through nodal threefolds.
This paper has been withdrawn because it has been superseded by arXiv:1203.1500 and the just submitted paper "Deforming Namikawa's fiber products", arXiv:1211.6329