Showing math.SGShow all
2 papers · 1 filter
math.SG2026
The cubic threefold is symplectically irrational
Jiaji Cai
We prove that smooth cubic threefolds are symplectically irrational. This recovers the classical irrationality theorem of Clemens-Griffiths. The obstruction is given by the formal…
math.SG2026
The quartic threefold is symplectically irrational
Jiaji Cai
We prove that smooth quartic threefolds are symplectically irrational: they cannot be related to projective space by a sequence of symplectic blow-ups, blow-downs, and deformations…