We call a non-discrete Euclidean building a Bruhat-Tits space if its automorphism group contains a subgroup that induces the subgroup generated by all the root groups of a root datum of the building at infinity. This is the class of non-discrete Euclidean buildings introduced and studied by Bruhat and Tits. We give the complete classification of Bruhat-Tits spaces whose building at infinity is the fixed point set of a polarity of an ambient building of type B_2, F_4 or G_2 associated with a Ree or Suzuki group endowed with the usual root datum. (In the B_2 and G_2 cases, this fixed point set is a building of rank one; in the F_4 case, it is a generalized octagon whose Weyl group is not crystallographic.) We also show that each of these Bruhat-Tits spaces has a natural embedding in the unique Bruhat-Tits space whose building at infinity is the corresponding ambient building.
翻译:我们称之为非分解的 Euclidean 建筑空间。 如果其自动形态组包含一个分组, 引导由无穷建筑根数据库的所有根组产生的分组。 这是由Bruhat 和 Tits 介绍和研究的非分解 Euclidean 建筑的类别。 我们给布鲁哈特- Tits 空间的完整分类, 其无穷的建筑是B_ 2、 F_ 4 或 G_ 2号环境建筑的两极分集, 与具有普通根数据库的Ree 或 Suzuki 组合有关。 ( 在 B_ 2 和 G_ 2 案例中, 这个固定点是一级建筑; 在 F_ 4 案例中, 这是一个通用的八边形, 其Wyl 组不是水晶学。 我们还显示, 这些布鲁哈特- Tits 空间的每个空间在独特的布鲁哈特- Tits 空间中都有自然嵌入。