论文标题
Grossberg-Karshon扭曲的立方体和犹豫的跳步避免
Grossberg-Karshon twisted cubes and hesitant jumping walk avoidance
论文作者
论文摘要
让$ g $是一个复杂的简单的半胶合代数组,排名$ r $和$ b $ borel子组。令$ \ mathbf i \ in [r]^n $为一个单词,让$ \ mathbf \ ell =(\ ell_1,\ dots,\ ell_n)$为一系列非阴性整数。 Grossberg和Karshon引入了与$ \ Mathbf I $和$ \ Mathbf \ ell $相关的虚拟晶格多层,称为扭曲的立方体,其晶格点编码了$ b $ prencentation的字符。更准确地说,根据一定密度函数的符号计数的扭曲立方体中的晶格点产生了由$ \ Mathbf I $和$ \ Mathbf \ Ell $确定的广义启动模块的特征。在最近的工作中,作者和原始的田纳拉邦精确地描述了当Grossberg-karshon Twisted Cube未扭曲时,即扭曲的立方体是一个封闭的凸多物件,在整数序列$ \ mathbf \ ell $中来自重量$λ$ $ g $。但是,并非每个整数序列$ \ Mathbf \ ell $都来自$ g $的重量。在本文中,我们使用$ \ MATHBF I $和$ \ MATHBF \ ELL $的组合物来解释与任何单词$ \ mathbf i $和任何整数序列$ \ mathbf \ ell $相关的grossberg-karshon扭曲的立方体和任何整数序列$ \ mathbf \ ell $。的确,我们证明Grossberg-karshon扭曲的立方体精确地是不介绍的。
Let $G$ be a complex simply-laced semisimple algebraic group of rank $r$ and $B$ a Borel subgroup. Let $\mathbf i \in [r]^n$ be a word and let $\mathbf \ell = (\ell_1,\dots,\ell_n)$ be a sequence of non-negative integers. Grossberg and Karshon introduced a virtual lattice polytope associated to $\mathbf i$ and $\mathbf \ell$ called a twisted cube, whose lattice points encode the character of a $B$-representation. More precisely, lattice points in the twisted cube, counted with sign according to a certain density function, yields the character of the generalized Demazure module determined by $\mathbf i$ and $\mathbf \ell$. In recent work, the author and Harada described precisely when the Grossberg-Karshon twisted cube is untwisted, i.e., the twisted cube is a closed convex polytope, in the situation when the integer sequence $\mathbf \ell$ comes from a weight $λ$ of $G$. However, not every integer sequence $\mathbf \ell$ comes from a weight of $G$. In the present paper, we interpret untwistedness of Grossberg-Karshon twisted cubes associated to any word $\mathbf i$ and any integer sequence $\mathbf \ell$ using the combinatorics of $\mathbf i$ and $\mathbf \ell$. Indeed, we prove that the Grossberg-Karshon twisted cube is untwisted precisely when $\mathbf i$ is hesitant-jumping-$\mathbf \ell$-walk-avoiding.