collaborators

8 papers

math.AG2026

Geometric Manin's conjecture in characteristic

Brian Lehmann, Sho Tanimoto

Geometric Manin's conjecture for complex Fano varieties describes the structure of the moduli space of curves. We propose a version of this conjecture in characteristic and des…

math.AG2026

Manin's conjecture for semi-integral curves and -connectedness

Qile Chen, Brian Lehmann, Sho Tanimoto

We explore log Manin's conjecture for integral points and its connections to -connectedness. We prove log Manin's conjecture for Campana rational curves and for $\math…

math.AG2026

A characterization of projective space via lengths of extremal rays

Osamu Fujino, Eric Jovinelly, Brian Lehmann +1

We prove a new characterization of complex projective space using lengths of extremal rays.

math.AG2026

Free curves and fundamental groups

Eric Jovinelly, Brian Lehmann, Eric Riedl

We show that klt Fano varieties and certain lc Fano varieties contain free higher-genus curves in their smooth loci. Our methods also allow us to find free curves on varieties in p…

math.AG2026

Optimal bounds in Bend-and-Break

Eric Jovinelly, Brian Lehmann, Eric Riedl

We improve the Bend-and-Break result of Miyaoka and Mori by establishing the optimal degree bound. Our result also yields optimal bounds on lengths of extremal rays of log canonica…

math.AG2025

Homological stability and Manin's conjecture for rational curves on quartic del Pezzo surfaces

Ronno Das, Brian Lehmann, Sho Tanimoto +1

We prove a version of Manin's conjecture (over for large) and the Cohen--Jones--Segal conjecture (over ) for maps from rational curves to split qua…