3 papers
math.AG2026
Torsion pairs and 3-fold flops
Parth Shimpi
This paper classifies t-structures on the local derived category of a 3-fold flopping contraction, that are intermediate with respect to the heart of perverse coherent sheaves. Equ…
math.AG2025
Kleinian orbifolds, Cohomological Hall Algebras, and Yangians
Francesco Sala, Olivier Schiffmann, Parth Shimpi
We establish, for each orbifold crepantly resolving a Kleinian singularity, the existence of the cohomological Hall algebra (COHA) of coherent sheaves supported on the exceptional…
math.AG2025
Simple complexes on a flopped curve
Parth Shimpi
Studying crepant blow-ups of (compound) du Val singularities, we classify complexes of coherent sheaves which admit no negative self-extensions -- such a complex, up to flops and m…