Finite Eulerian posets which are binomial, Sheffer or triangular

In this paper we study finite Eulerian posets which are binomial, Sheffer or triangular. These important classes of posets are related to the theory of generating functions and to geometry. The results of this paper are organized as follows:

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We completely determine the structure of Eulerian binomial posets and, as a conclusion, we are able to classify factorial functions of Eulerian binomial posets.

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We give an almost complete classification of factorial functions of Eulerian Sheffer posets by dividing the original question into several cases.

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In most cases above, we completely determine the structure of Eulerian Sheffer posets, a result stronger than just classifying factorial functions of these Eulerian Sheffer posets.

We also study Eulerian triangular posets. This paper answers questions posed by R. Ehrenborg and M. Readdy. This research is also motivated by the work of R. Stanley about recognizing the boolean lattice by looking at smaller intervals.     

On poset Boolean algebras of scattered posets with finite width

We prove that the poset algebra of every scattered poset with finite width is embeddable in the poset algebra of a well ordered poset.Mathematics Subject Classification (2000):Primary 03G05, 06A06, 06A11; Secondary 08A05, 54G12     

关于蕴涵BCK—代数的伴随半群

我们证明了蕴涵BCK-代数的伴随半群是一个上半格;具有条件（s)的蕴涵BCK-代数的伴随半群是一个广义布尔代数。更进一步证明了有界蕴涵BCK-代数的伴随半群是一个布尔代数。     

Matrices with convolutions of binomial functions and Krawtchouk matrices

We introduce a class S_N of matrices whose elements are terms of convolutions of binomial functions of complex numbers. A multiplication theorem is proved for elements of S_N. The multiplication theorem establishes a homomorphism of the group of 2 by 2 nonsingular matrices with complex elements into a group G_N contained in S_N. As a direct consequence of representation theory, we also present related spectral representations for special members of G_N. We show that a subset of G_N constitutes the system of Krawtchouk matrices, which extends published results for the symmetric case.     

On clones, transformation monoids, and finite Boolean algebras

We prove that, for a finite Boolean algebra, there exist only finitely many clones which consist of polynomial functions of the algebra and contain the monoid of its unary polynomial functions. Received January 7, 2000; accepted in final form December 13, 2000.     

Subdirect decompositions and the radical of a generalized Boolean algebra extension of a lattice ordered group

The extension of a lattice ordered group A by a generalized Boolean algebra B will be denoted by A _B . In this paper we apply subdirect decompositions of A _B for dealing with a question proposed by Conrad and Darnel. Further, in the case when A is linearly ordered we investigate (i) the completely subdirect decompositions of A _B and those of B, and (ii) the values of elements of A _B and the radical R(A _B ).     

On the Product and Factorization of Lattice Implication Algebras

In this paper,the concepts of product and factorization of lattice implication algebra areproposed,the relation between lattice implication product algebra and its factors and some properties oflattice implication product algebras are discussed.     

q-Weighted log-concavity and q-product theorem on the normality of posets

We show that q-weighted log-concavity and the strict normalized matching property are preserved under the q-direct product over weighted posets. As consequences, two classes of weighted posets including the finite linear lattices are strictly q-weighted log-concave and strictly normal.     

Some representations of the multivariate Bernoulli and binomial distributions

Multivariate but vectorized versions for Bernoulli and binomial distributions are established using the concept of Kronecker product from matrix calculus. The multivariate Bernoulli distribution entails a parameterized model, that provides an alternative to the traditional log-linear model for binary variables.     

Games of Chains and Cutsets in the Boolean Lattice II

Let 2 ^[n] denote the poset of all subsets of [n]={1,2,...,n} ordered by inclusion. Following Gutterman and Shahriari (Order 14, 1998, 321–325) we consider a game G _n (a,b,c). This is a game for two players. First, Player I constructs a independent maximal chains in 2 ^[n]. Player II will extend the collection to a+b independent maximal chains by finding another b independent maximal chains in 2 ^[n]. Finally, Player I will attempt to extend the collection further to a+b+c such chains. The last Player who is able to complete her move wins. In this paper, we complete the analysis of G _n (a,b,c) by considering its most difficult instance: when c=2 and a+b+2=n. We prove, the rather surprising result, that, for n7, Player I wins G _n (a,n–a–2,2) if and only if a3. As a consequence we get results about extending collections of independent maximal chains, and about cutsets (collections of subsets that intersect every maximal chain) of minimum possible width (the size of largest anti-chain).     

On the hierarchical product of graphs and the generalized binomial tree

In this article we follow the study of the hierarchical product of graphs, an operation recently introduced in the context of networks. A well-known example of such a product is the binomial tree which is the (hierarchical) power of the complete graph on two vertices. An appealing property of this structure is that all the eigenvalues are distinct. Here we show how to obtain a graph with this property by applying the hierarchical product. In particular, we propose a generalization of the binomial tree and study some of its main properties.     

Generalizations of Eulerian partially ordered sets, flag numbers, and the Möbius function

A partially ordered set is r-thick if every nonempty open interval contains at least r elements. This paper studies the flag vectors of graded, r-thick posets and shows the smallest convex cone containing them is isomorphic to the cone of flag vectors of all graded posets. It also defines a k-analogue of the Möbius function and k-Eulerian posets, which are 2k-thick. Several characterizations of k-Eulerian posets are given. The generalized Dehn-Sommerville equations are proved for flag vectors of k-Eulerian posets. A new inequality is proved to be valid and sharp for rank 8 Eulerian posets.ResumeUn ensemble partiellement ordonné est r-épais si chacun de ses intervalles ouverts non-vides contient au moins r éléments. Dans cet article nous étudions les vecteurs drapeaux des ensembles partiellement ordonnés gradués r-épais. Nous démontrons que le cône le plus petit contenant ces vecteurs est isomorphe au cône des vecteurs drapeaux des ensembles partiellement ordonnés gradués quelconques. Nous définissons aussi un k-analogue de la fonction de Möbius et des ensembles partiellement ordonnés k-eulériens qui sont 2k-épais. Nous caractérisons les ensembles partiellement ordonnés k-eulériens de plusieurs manières, et généralisons les équations de Dehn-Sommerville pour le vecteur drapeaux d'un ensemble partiellement ordonné k-eulérien. Nous démontrons une nouvelle inégalité optimale pour les ensembles partiellement ordonnés eulériens de rang 8.     

Analysis of the Bernstein basis functions: an approach to combinatorial sums involving binomial coefficients and Catalan numbers

We give some alternative forms of the generating functions for the Bernstein basis functions. Using these forms,we derive a collection of functional equations for the generating functions. By applying these equations, we prove some identities for the Bernstein basis functions. Integrating these identities, we derive a variety of identities and formulas, some old and some new, for combinatorial sums involving binomial coefficients, Pascal's rule, Vandermonde's type of convolution, the Bernoulli polynomials, and the Catalan numbers. Copyright © 2014 John Wiley & Sons, Ltd.     

Coproducts of bounded distributive lattices: cancellation

Let denote the coproduct of the bounded distributive lattices L and M. At the 1981 Banff Conference on Ordered Sets, the following question was posed: What is the largest class L of finite distributive lattices such that, for every non-trivial Boolean lattice B and every implies ? In this note, the problem is solved. Received March 2, 1999; accepted in final form July 10, 2000.     

The free orthomodular lattice on countably many generators is a subalgebra of the free orthomodular lattice on three generators

We show every at most countable orthomodular lattice is a subalgebra of one generated by three elements. As a corollary we obtain that the free orthomodular lattice on countably many generators is a subalgebra of the free orthomodular lattice on three generators. This answers a question raised by Bruns in 1976 [2] and listed as Problem 15 in Kalmbach's book on orthomodular lattices [6]. Received April 12, 2001; accepted in final form May 6, 2002.     

The connected partition lattice of a graph and the reconstruction conjecture

Previously we showed that many invariants of a graph can be computed from its abstract induced subgraph poset, which is the isomorphism class of the induced subgraph poset, suitably weighted by subgraph counting numbers. In this paper, we study the abstract bond lattice of a graph, which is the isomorphism class of the lattice of distinct unlabelled connected partitions of a graph, suitably weighted by subgraph counting numbers. We show that these two abstract posets can be constructed from each other except in a few trivial cases. The constructions rely on certain generalisations of a lemma of Kocay in graph reconstruction theory to abstract induced subgraph posets. As a corollary, trees are reconstructible from their abstract bond lattice. We show that the chromatic symmetric function and the symmetric Tutte polynomial of a graph can be computed from its abstract induced subgraph poset. Stanley has asked if every tree is determined up to isomorphism by its chromatic symmetric function. We prove a counting lemma, and indicate future directions for a study of Stanley's question.     

基于max-product复合的模糊矩阵幂序列的收敛性及其分类

主要讨论模糊矩阵在max-product复合意义下的收敛性.通过对模糊矩阵元素的有限收敛、无限收敛、有限振荡、无限振荡的情况的讨论,引入模糊矩阵的有限收敛、无限收敛、有限振荡、无限振荡的概念,证明模糊矩阵在max-product复合意义下要么有限收敛,要么无限收敛,要么有限振荡,要么无限振荡,给出了模糊矩阵在max-product复合意义下收敛性的完整结论,并澄清已有文献中的一些错误.最后给出基于max-product复合的模糊矩阵幂序列的分类情况.     

Singly Periodic Solutions of the Allen-Cahn Equation and the Toda Lattice

The Allen-Cahn equation ? Δu = u ? u ³ in ?² has family of trivial singly periodic solutions that come from the one dimensional periodic solutions of the problem ?u″ =u ? u ³. In this paper we construct a non-trivial family of singly periodic solutions to the Allen-Cahn equation. Our construction relies on the connection between this equation and the infinite Toda lattice. We show that for each one-soliton solution to the infinite Toda lattice we can find a singly periodic solution to the Allen-Cahn equation, such that its level set is close to the scaled one-soliton. The solutions we construct are analogues of the family of Riemann minimal surfaces in ?³.     

A new approach to the representation of trigonometric and hyperbolic functions by infinite products

An innovative technique is developed for obtaining infinite product representations for some elementary functions. The technique is based on the comparison of alternative expressions of Green's functions constructed by two different methods. Some standard boundary value problems are considered posed for two-dimensional Laplace equation on regions of a regular configuration. Classical closed analytic form of Green's functions for such problems are compared against those obtained by the method of images in the form of infinite products. This yields a number of new infinite product representations for trigonometric and hyperbolic functions.