New realization of $ı$quantum groups via $\Delta$-Hall algebras

Jiayi Chen, Yanan Lin, Shiquan Ruan

For an essentially small hereditary abelian category $\mathcal{A}$, we define a new kind of algebra ${\mathcal{H}}_{\Delta }(\mathcal{A})$, called the $\Delta$-Hall algebra of $\mathcal{A}$. The…