The Sperner Property in Geometric and Partition Lattices

1990 ◽  
pp. 298-304 ◽  
Author(s):  
Jerrold R. Griggs
2020 ◽  
Vol DMTCS Proceedings, 28th... ◽  
Author(s):  
Henri Mühle

International audience We prove that the noncrossing partition lattices associated with the complex reflection groups G(d, d, n) for d, n ≥ 2 admit a decomposition into saturated chains that are symmetric about the middle ranks. A consequence of this result is that these lattices have the strong Sperner property, which asserts that the cardinality of the union of the k largest antichains does not exceed the sum of the k largest ranks for all k ≤ n. Subsequently, we use a computer to complete the proof that any noncrossing partition lattice associated with a well-generated complex reflection group is strongly Sperner, thus affirmatively answering a special case of a question of D. Armstrong. This was previously established only for the Coxeter groups of type A and B.


10.37236/8874 ◽  
2020 ◽  
Vol 27 (3) ◽  
Author(s):  
Lawrence H. Harper ◽  
Gene B. Kim ◽  
Neal Livesay

There are several classes of ranked posets related to reflection groups which are known to have the Sperner property, including the Bruhat orders and the generalized noncrossing partition lattices (i.e., the maximal intervals in absolute orders).  In 2019, Harper–Kim proved that the absolute orders on the symmetric groups are (strongly) Sperner.  In this paper, we give an alternate proof that extends to the signed symmetric groups and the dihedral groups.  Our simple proof uses techniques inspired by Ford–Fulkerson's theory of networks and flows, and a product theorem.


1989 ◽  
Vol 29 (3) ◽  
pp. 507-508 ◽  
Author(s):  
A. G. Pinus

1992 ◽  
pp. 106-122 ◽  
Author(s):  
Ivan Rival ◽  
Miriam Stanford
Keyword(s):  

2018 ◽  
Vol 79 (2) ◽  
Author(s):  
James Emil Avery ◽  
Jean-Yves Moyen ◽  
Pavel Růžička ◽  
Jakob Grue Simonsen
Keyword(s):  

2003 ◽  
Vol 43 (5) ◽  
pp. 722-726
Author(s):  
Sung Soo Jung ◽  
Seung Il Cho ◽  
Yong Bong Lee ◽  
Woo Seop Lee

Author(s):  
T. P. Speed

AbstractThe role played by the Möbius function of the lattice of all partitions of a set in the theory of k-statistics and their generalisations is pointer out and the main results conscerning these statistics are drived. The definitions and formulae for the expansion of products of generalished k-statistics are presented from this viewpoint and applied to arrays of random variables whos moments satisfy stitable symmentry constraints. Applications of the theory are given including the calculation of (joint) cumulants of k-statistics, the minimum variace estimation of (generalised) moments and the asymptotic behaviour of generalised k-statistics viewed as (reversed) martingales.


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