MATSUSHITA, D: On smooth 4-fold flops
Saitama Mathematical Journal 1997(Vol. 15) pp.17-54
A 3-fold flop preserves the analytic structure.
Especially, the flop of a smooth 3-fold is smooth.
On the contrary, a 4-fold flop does not preserve the analytic
In this note, we show by using toric geometry that every isolated Gorenstein
terminal cyclic quotient singularity arises on flops of a smooth 4-fold
1991 AMS subject classification
Primary 14J35, Secondary 14E05, 14M25