Qixiao Ma

collaborators

4 papers

math.AG2019

Brauer class over the Picard scheme of totally degenerate stable curves

Qixiao Ma

We study the Brauer class rising from the obstruction to the existence of tautological line bundles on the Picard scheme of curves. We determine the period and index of the Brauer…

math.AG2019

Conics associated with totally degenerate curves

Qixiao Ma

Let $k$ be a field. Let $X / k$ be a stable curve whose geometric irreducible components are smooth rational curves. Taking Stein factorization of its normalization, we get a conic.…

math.AG2019

Closed points on cubic hypersurfaces

Qixiao Ma

We generalize some results of Coray on closed points on cubic hypersurfaces. We show certain symmetric products of cubic hypersurfaces are stably birational.

math.AG2019

Some properties of a Brauer class

Qixiao Ma

Let $X$ be a smooth proper curve defined over a field $k$ . The representability of the relative Picard functor is obstructed by a class $α \in Br (Pic_{X / k})$ . We sh…