activity
20242026
collaborators

9 papers

math.AG2026

The theorem of Maehara-Severi for maps of general type

Finn Bartsch, Ariyan Javanpeykar, Erwan Rousseau

We prove a finiteness result for dominant rational maps whose orbifold base is of general type. Our finiteness result generalizes Maehara's theorem that a given variety dominates o…

math.AG2026

Weakly special varieties, Campana stacks, and Remarks on Orbifold Mordell

Finn Bartsch, Ariyan Javanpeykar

We construct the first weakly special surfaces that are not Campana-special, including the complement of the plane curve in . We prove that the set of $\…

math.AG2026

The map to the orbifold base need not be an orbifold map

Finn Bartsch

We give an explicit example of a fibration between smooth projective varieties whose "orbifold base" in the sense of Campana has the property that the indu…

math.AG2025

More counterexamples to the Arithmetic Puncturing Problem

Finn Bartsch

We construct examples of threefolds with terminal singularities (resp. surfaces with canonical singularities) which are special in the sense of Campana, have a potentially dense se…

math.AG2025

The Kobayashi pseudometric in the presence of log-terminal singularities

Finn Bartsch

We show that the Kobayashi pseudometric is well-behaved under resolution of log-terminal singularities. This answers a question of Kamenova and Lehn.

math.AG2025

On the finiteness of maps into simple abelian varieties satisfying certain tangency conditions

Finn Bartsch

We show that given a simple abelian variety and a normal variety defined over a finitely generated field of characteristic zero, the set of non-constant morphisms $V \t…