3 papers
math.AG2025
There are no exotic compact moduli of sheaves on a curve
Andres Fernandez Herrero, Dario Weissmann, Xucheng Zhang
We study moduli of coherent sheaves of some given degree and positive rank on a curve. We show that there is only one nonempty open condition on families of sheaves that yields a u…
math.AG2024
Distinguishing Algebraic Spaces from Schemes
Andres Fernandez Herrero, Dario Weißmann, Xucheng Zhang
We introduce local invariants of algebraic spaces and stacks which measure how far they are from being a scheme. Using these invariants, we develop mostly topological criteria to d…
math.AG2024
S-equivalence for algebraic stacks
Xucheng Zhang
We generalize the notion of S-equivalence, previously defined for semistable vector bundles, to points in arbitrary algebraic stacks and use it to describe the identification of po…