Remarks on computing Green functions

关于$\tilde{A}_{n,1}$型箭图的极大Green序列长度的注记

Remarks on lengths of maximal green sequences for quivers of type $\tilde{A}_{n,1}$

由B. Keller是在绿色顶点处的一系列突变。T. Br于斯特尔湾Dupont和M. Pérotin表明，对于一个非循环的偏序集，极大格林序列被实现为支撑倾斜模偏序集的Hasse偏序集中的极大路。他们还考虑了最大绿色序列的可能长度。本文利用倾斜突变理论计算了$A$型和$\tilde{A}_{n,1}$型随机序列的最大绿序列的可能长度。

Computing Green functions in small characteristic

Let $G(q)$ be a finite group of Lie type over a field with $q$ elements, where $q$ is a prime power. The Green functions of $G(q)$, as defined by Deligne and Lusztig, are known in \textit{almost} all cases by work of Beynon--Spaltenstein, Lusztig und Shoji. Open cases exist for groups of exceptional type ${^2\!E}_6$, $E_7$, $E_8$ in small characteristics. We propose a general method for dealing with these cases, which procedes by a reduction to the case where $q$ is a prime and then uses computer algebra techniques. In this way, all open cases in type ${^2\!E}_6$, $E_7$ are solved, as well as …

Remarks on a triangulated version of Auslander-Kleiner's Green correspondence

For a finite group $G$ and an algebraically closed field $k$ of characteristic $p>0$ for any indecomposable finite dimensional $kG$-module $M$ with vertex $D$ and a subgroup $H$ of $G$ containing $N_G(D)$ there is a unique indecomposable $kH$-module $N$ of vertex $D$ being a direct summand of the restriction of $M$ to $H$. This correspondence, called Green correspondence, was generalised by Auslander-Kleiner to the situation of pairs of adjoint functors between additive categories. In the original situation of group rings Carlson-Peng-Wheeler proved that this correspondence is actually restric…

Generalized Green functions and unipotent classes for finite reductive groups, III

Lusztig's algorithm of computing generalized Green functions of reductive groups involves an ambiguity of certain scalars. In this paper, for reductive groups of classical type with arbitrary characteristic, we determine those scalars explicitly, and eliminate the ambiguity. Our results imply that all the generalized Green functions of classical type are computable.

有限约化群的广义格林函数和幂幺类，II

Generalized Green functions and unipotent classes for finite reductive groups, II

在“有限约化群的广义格林函数和幂幺类”中，我们确定了SL_n情形下计算广义格林函数的算法中涉及的某些未知标量。在本文中，我们考虑了具有任意特征的典型群Sp_{2n}，SO_N的情形。我们的结果使我们，特别是，计算格林函数在坏的特征的情况下，这是不知道的。

Generalized Green functions associated to complex reflection groups

In this paper, we consider the set of r-symbols in a full generality. We construct Hall-Littlewood functions and Kostka functions associated to those r-symbols. We also discuss a multi-parameter version of those functions. We show that there exists a general algorithm of computing multi-parameter Kostka functions. As an application, we show that the generalized Green functions of symplectic groups can be described combinatorially in terms of those (one-parameter) Kostka functions.