نتایج جستجو برای: shellable complex

تعداد نتایج: 783934  

2007
JAKOB JONSSON VOLKMAR WELKER

Let S be a finite alphabet. An injective word over S is a word over S such that each letter in S appears at most once in the word. We study Boolean cell complexes of injective words over S and their commutation classes. This generalizes work by Farmer and by Björner and Wachs on the complex of all injective words. Specifically, for an abstract simplicial complex ∆, we consider the Boolean cell ...

Journal: :Proceedings of the American Mathematical Society 1981

Journal: :Electr. J. Comb. 2011
Jay Schweig

We prove a theorem allowing us to find convex-ear decompositions for rankselected subposets of posets that are unions of Boolean sublattices in a coherent fashion. We then apply this theorem to geometric lattices and face posets of shellable complexes, obtaining new inequalities for their h-vectors. Finally, we use the latter decomposition to give a new interpretation to inequalities satisfied ...

2018
Duško Jojić

We use a concrete shelling order of chessboard complexes ∆n,m for m > 2n − 1 to describe the type of each facet of ∆n,m in this order. Further, we find some recursive relations for h-vector, describe the generating facets of shellable ∆n,m and show that the number of generating facets of ∆n,m is the value of a special Poisson-Charlier polynomial pn(m). Some of these results can be extended to c...

Journal: :Order 2013
Stephan Foldes Russ Woodroofe

Rival and Zaguia showed that the antichain cutsets of a finite Boolean lattice are exactly the level sets. We show that a similar characterization of antichain cutsets holds for any strongly connected poset of locally finite height. As a corollary, we characterize the antichain cutsets in semimodular lattices, supersolvable lattices, Bruhat orders, locally shellable lattices, and many more. We ...

2017
GIOVANNI PAOLINI

We prove that the posets of connected components of intersections of toric and elliptic arrangements defined by root systems are EL-shellable and we compute their homotopy type. Our method rests on Bibby’s description of such posets by means of “labeled partitions”: after giving an EL-labeling and counting homology chains for general posets of labeled partitions, we obtain the stated results by...

2006
BOGDAN ICHIM

Following a construction of Stanley we consider toric face rings associated to rational pointed fans. This class of rings is a common generalization of the concepts of Stanley–Reisner and affine monoid algebras. The main goal of this article is to unify parts of the theories of Stanley–Reisnerand affine monoid algebras. We consider (nonpure) shellable fan’s and the Cohen–Macaulay property. More...

Journal: :Ars Mathematica Contemporanea 2021

We consider families of finite sets that we call shellable and have been characterized by Chang Hirst Hughes as being the admit unique solutions to Hall's marriage problem. In this paper, introduce a natural generalization Edelman Greene's balanced tableaux involves satisfy Condition certain words in $[n]^m$, then prove can be strong existence condition relating generalization. As consequence c...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تربیت معلم تهران - دانشکده علوم 1370

determination of uranium in natural water and complex solutions using ion exchange chromatography: a combined procedure using ion exchange chromatography and uv-vis spectrophotometry techniques has been developed to measure uranum in natural water and complex solutions. after conditicing , one hundred milli liters of sample solutions have been passed through an ion exchange column,pachked with ...

Journal: :Discrete Mathematics 2014
Mahir Bilen Can Tim Twelbeck

In this manuscript we study inclusion posets of Borel orbit closures on (symmetric) matrices. In particular, we show that the Bruhat poset of partial involutions is a lexicographically shellable poset. We determine which subintervals of the Bruhat posets are Eulerian, and moreover, by studying certain embeddings of the symmetric groups and their involutions into rook matrices and partial involu...

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