Connecting certain rigid birational non-homeomorphic Calabi--Yau threefolds via Hilbert scheme
arXiv:math/0703315
Abstract
We shall give an explicit pair of birational projective Calabi--Yau threefolds which are rigid, non-homeomorphic, but are connected by projective flat deformation over some connected base scheme.
15 pages 7 figures many typos are corrected