منابع مشابه
Subword complexes, cluster complexes, and generalized multi-associahedra
In this paper, we use subword complexes to provide a uniform approach to finite-type cluster complexes and multi-associahedra. We introduce, for any finite Coxeter group and any nonnegative integer k, a spherical subword complex called multi-cluster complex. For k = 1, we show that this subword complex is isomorphic to the cluster complex of the given type. We show that multi-cluster complexes ...
متن کاملInvolution Subword Complexes in Coxeter Groups
Let (W,S) be a Coxeter system. An element in W and an ordered list of elements in S give us a subword complex, as defined by Knutson and Miller. We define the “fish product” between an involution in W and a generator in S, which is also discussed by Hultman. This “fish product” always produces an involution. The structure of the involution subword complex ∆̂(Q,w) behaves very similarly to the re...
متن کاملSchubert Patches Degenerate to Subword Complexes
We study the intersections of general Schubert varieties Xw with permuted big cells, and give an inductive degeneration of each such “Schubert patch” to a StanleyReisner scheme. Similar results had been known for Schubert patches in various types of Grassmannians. Wemaintain reducedness using the results of [Knutson 2007] on automatically reduced degenerations, or throughmore standard cohomolog...
متن کاملBott-Samelson Varieties, Subword Complexes and Brick Polytopes
Bott-Samelson varieties factor the flag variety G/B into a product of CP’s with a map into G/B. These varieties are mostly studied in the case in which the map into G/B is birational; however in this paper we study fibers of this map when it is not birational. We will see that in some cases this fiber is a toric variety. In order to do so we use the moment map of a Bott-Samelson variety to tran...
متن کاملSchubert Varieties, Subword Complexes, Frobenius Splitting, and Bruhat Atlases
We consider stratifications of schemes by subvarieties, and introduce the notion of a stratification generated by a collection of (reduced) subschemes. We recall some basics of Gröbner degenerations (just for lex order) and Stanley-Reisner theory. We then state the main theorem, that the lex init of a Kazhdan-Lusztig variety in BottSamelson coördinates is the Stanley-Reisner scheme of a subword...
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ژورنال
عنوان ژورنال: Russian Mathematical Surveys
سال: 2014
ISSN: 0036-0279,1468-4829
DOI: 10.1070/rm2014v069n03abeh004903