activity
20192026
most citedBPS Lie algebras for totally negative 2-Calabi-Yau categories and nonabelian Hodge theory for stacks

6 citations · 13 across the 17 of their papers we have counts for

collaborators

17 papers

math.RT2026

Commutativity of nilpotent cohomological Hall algebras of

Lucien Hennecart

In this paper, we prove that both the seminilpotent and the fully nilpotent CoHAs of are commutative. This result is in strong contrast with the CoHA of $\mathbf{A}^…

math.AG2026

Hecke operators on symplectic surfaces and -independence

Ben Davison, Lucien Hennecart, Tasuki Kinjo +2

We prove Toda's chi-independence conjecture for the BPS cohomology of moduli spaces of one-dimensional sheaves on quasi-projective symplectic surfaces, relative to the Chow variety…

math.AG2026

The Deligne-Simpson problem via 2-Calabi-Yau categories

Lucien Hennecart

We provide a short proof of the necessity of Crawley-Boevey's condition in his solution to the Deligne-Simpson problem. The proof relies on the local neighbourhood theorem for -…

math.RT2026

Degenerations of CoHAs of 2-Calabi-Yau categories

Lucien Hennecart, Shivang Jindal

By work of Davison and Meinhardt, the cohomological Hall algebra of a symmetric quiver with potential admits a geometrically defined filtration (the perverse filtration) whose asso…

math.AG2025

The BPS decomposition theorem

Lucien Hennecart, Tasuki Kinjo

We prove the BPS decomposition theorem (a.k.a. cohomological integrality theorem) decomposing the cohomology of smooth symmetric stacks into the Weyl-invariant part of the cohomolo…

math.RT2025

Cohomological Mackey formula for quotient stacks

Lucien Hennecart

In this paper, we construct a restriction morphism on the critical cohomology of an equivariant Landau-Ginzburg model associated to a representation of a reductive group equipped w…

math.AG2024

Cohomological integrality for symmetric quotient stacks

Lucien Hennecart

In this paper, we establish the sheafified version of the cohomological integrality conjecture for stacks obtained as a quotient of a smooth affine symmetric algebraic variety by a…

math.RT2024

Cohomological integrality for weakly symmetric representations of reductive groups

Lucien Hennecart

In this paper, we prove the integrality conjecture for quotient stacks arising from weakly symmetric representations of reductive groups. Our main result is a decomposition of the…

math.AG2023★ 1 cited

Nonabelian Hodge isomorphisms for stacks and cohomological Hall algebras

Lucien Hennecart

In this paper, we complete the nonabelian Hodge theory (NAHT) triangle of isomorphisms for stacks between the Borel-Moore homologies of the Dolbeault, Betti, and de Rham moduli sta…

math.RT2023★ 4 cited

BPS algebras and generalised Kac-Moody algebras from 2-Calabi-Yau categories

Ben Davison, Lucien Hennecart, Sebastian Schlegel Mejia

We determine the structure of the BPS algebra of 2-Calabi-Yau Abelian categories for which the stack of objects admits a good moduli space. We prove that this algebra is isomorphic…

math.RT2022★ 6 cited

BPS Lie algebras for totally negative 2-Calabi-Yau categories and nonabelian Hodge theory for stacks

Ben Davison, Lucien Hennecart, Sebastian Schlegel Mejia

We define and study a sheaf-theoretic cohomological Hall algebra for suitably geometric Abelian categories of homological dimension at most two, and a sheaf-theoretic…

math.RT2022

Geometric realisations of the unipotent enveloping algebra of a quiver

Lucien Hennecart

We compare and generalise the various geometric constructions (due to Ringel, Lusztig, Schofield, Bozec, Davison...) of the unipotent generalised Kac-Moody algebra associated with…

math.RT2022

A Quiver Analogue of Higman's Conjecture

Lucien Hennecart, Nikolai Perry

An unresolved conjecture by Graham Higman states that for all the number of conjugacy classes of the group of unitriangular matrices with entries in the fini…

math.AG2021

Perverse sheaves with nilpotent singular support on the stack of coherent sheaves on an elliptic curve

Lucien Hennecart

We define a stratification of the moduli stack of coherent sheaves on an elliptic curve which allows us (1) to give an explicit description of the irreducible components of the glo…

math.AG2020★ 2 cited

Microlocal characterization of Lusztig sheaves for affine quivers and -loops quivers

Lucien Hennecart

We prove that for extended Dynkin quivers, simple perverse sheaves in Lusztig category are characterized by the nilpotency of their singular support. This proves a conjecture of Lu…

math.RT2020

Asymptotic behaviour of Kac polynomials

Lucien Hennecart

We conjecture a formula supported by computations for the valuation of Kac polynomials of a quiver, which only depends on the number of loops at each vertex. We prove a convergence…

math.QA2019

Isotropic cuspidal functions in the Hall algebra of a quiver

Lucien Hennecart

From the structure of the category of representations of an affine cycle-free quiver, we determine an explicit linear form on the space of regular cuspidal functions over a finite…