André permutations, lexicographic shellability and the $cd$-index of a convex polytope

نویسندگان

چکیده

برای دانلود باید عضویت طلایی داشته باشید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Lexicographic shellability of partial involutions

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...

متن کامل

Rees products and lexicographic shellability

We use the theory of lexicographic shellability to provide various examples in which the rank of the homology of a Rees product of two partially ordered sets enumerates some set of combinatorial objects, perhaps according to some natural statistic on the set. Many of these examples generalize a result of J. Jonsson, which says that the rank of the unique nontrivial homology group of the Rees pr...

متن کامل

Quotient Complexes and Lexicographic Shellability

Let n,k,k and n,k,h , h < k, denote the intersection lattices of the k-equal subspace arrangement of type Dn and the k, h-equal subspace arrangement of type Bn respectively. Denote by SB n the group of signed permutations. We show that ( n,k,k )/SB n is collapsible. For ( n,k,h )/S B n , h < k, we show the following. If n ≡ 0 (mod k), then it is homotopy equivalent to a sphere of dimension 2n k...

متن کامل

Lexicographic Shellability for Balanced Complexes

We introduce a notion of lexicographic shellability for pure, balanced boolean cell complexes, modelled after the CL-shellability criterion of Björner and Wachs (Adv. in Math. 43 (1982), 87–100) for posets and its generalization by Kozlov (Ann. of Comp. 1(1) (1997), 67–90) called CC-shellability. We give a lexicographic shelling for the quotient of the order complex of a Boolean algebra of rank...

متن کامل

A lexicographic shellability characterization of geometric lattices

Geometric lattices are characterized as those finite, atomic lattices such that every atom ordering induces a lexicographic shelling given by an edge labeling known as a minimal labeling. Equivalently, geometric lattices are shown to be exactly those finite lattices such that every ordering on the join-irreducibles induces a lexicographic shelling. This new characterization fits into a similar ...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

ژورنال

عنوان ژورنال: Transactions of the American Mathematical Society

سال: 1993

ISSN: 0002-9947,1088-6850

DOI: 10.1090/s0002-9947-1993-1094560-9