7 papers · 1 filter
Weierstrass models
Ying Zong
Elliptic K3 admit contraction to plane models, the Weierstrass models. We define a higher dimensional notion of Weierstrass models, show that they are compactification of torsors i…
Minimal models of L*
Ying Zong
Let S be an algebraic space, A an S-abelian algebraic space, L an S-fiberwise numerically trivial invertible module on A, and L* the sheaf of regular sections of L considered as a…
Equidimensionality and regularity
Ying Zong
The existence of an equidimensional morphism f with etale local sections from a regular algebraic space X to a locally noetherian normal algebraic space S of characteristic zero wi…
Group schemes of square free order
V. Kumar Murty, Ying Zong
Every finite flat finitely presented group scheme G of square free order over a scheme S can be written as an extension of a finite etale S-group scheme G" by a commutative finite…
Basic finite étale equivalence relations
Ying Zong
We characterize quotient of a non-degenerate abelian fibration by a finite étale equivalence relation. We show that non-uniruled degenerations of each such quotient tend to be almo…
Almost non-degenerate abelian fibrations
Ying Zong
We provide evidence for the Principle : Non-uniruled abelian fibrations are almost non-degenerate.
A going-up theorem
Ying Zong
We generalize certain arguments in Zariski's irregularity theorem on cyclic multiple planes.