for Journals by Title or ISSN for Articles by Keywords help

Publisher: Springer-Verlag   (Total: 2345 journals)

 Annals of Combinatorics   [SJR: 0.849]   [H-I: 15]   [3 followers]  Follow         Hybrid journal (It can contain Open Access articles)    ISSN (Print) 0219-3094 - ISSN (Online) 0218-0006    Published by Springer-Verlag  [2345 journals]
• Homotopy Types of Frobenius Complexes
• Authors: Shouta Tounai
Abstract: Let Λ be a submonoid of the additive monoid $${\mathbb{N}}$$ . There is a natural order on Λ defined by $${\lambda \leq \lambda +\mu}$$ for $${\lambda,\mu \in \Lambda}$$ . A Frobenius complex of Λ is defined to be the order complex of an open interval of Λ. Suppose $${r \geq 2}$$ and let $${\rho}$$ be a reducible element of Λ. We construct the additive monoid $${\Lambda[\rho/r]}$$ obtained from Λ by adjoining a solution to the equation $${r\alpha=\rho}$$ . We show that any Frobenius complex of $${\Lambda[\rho/r]}$$ is homotopy equivalent to a wedge of iterated suspensions of Frobenius complexes of Λ. As a consequence, we derive a formula for the multi-graded Poincaré series associated to $${\Lambda[\rho/r]}$$ . As an application, we determine the homotopy types of the Frobenius complexes of some additive monoids. For example, we show that if Λ is generated by a finite geometric sequence, then any Frobenius complex of Λ is homotopy equivalent to a wedge of spheres.
PubDate: 2017-05-17
DOI: 10.1007/s00026-017-0353-1

• The Enumeration of Permutations Avoiding 3124 and 4312
• Authors: Jay Pantone
Abstract: We find the generating function for the class of all permutations that avoid the patterns 3124 and 4312 by showing that it is an inflation of the union of two geometric grid classes.
PubDate: 2017-05-12
DOI: 10.1007/s00026-017-0352-2

• Sharp Concentration Inequalities for Deviations from the Mean for Sums of
• Authors: Harrie Hendriks; Martien C. A. van Zuijlen
Abstract: For a fixed unit vector $${a = (a_1, a_2,..., a_n) \in S^{n-1}}$$ , that is, $${\sum^n_{i=1} a^2_1 = 1}$$ , we consider the 2 n signed vectors $${\varepsilon = (\varepsilon_1, \varepsilon_2,..., \varepsilon_n) \in \{-1, 1\}^n}$$ and the corresponding scalar products $${a \cdot \varepsilon = \sum^n_{i=1} a_i \varepsilon_i}$$ . In [3] the following old conjecture has been reformulated. It states that among the 2 n sums of the form $${\sum \pm a_i}$$ there are not more with $${ \sum^n_{i=1} \pm a_i > 1}$$ than there are with $${ \sum^n_{i=1} \pm a_i \leq 1}$$ . The result is of interest in itself, but has also an appealing reformulation in probability theory and in geometry. In this paper we will solve an extension of this problem in the uniform case where $${a_1 = a_2 = \cdot\cdot\cdot = a_n = n^{-1/2}}$$ . More precisely, for S n being a sum of n independent Rademacher random variables, we will give, for several values of $${\xi}$$ , precise lower bounds for the probabilities $$P_n: = \mathbb{P} \{-\xi \sqrt{n} \leq S_n \leq \xi \sqrt{n}\}$$ or equivalently for $$Q_n: = \mathbb{P} \{-\xi \leq T_n \leq \xi \},$$ where $${T_n}$$ is a standardized binomial random variable with parameters n and $${p = 1/2}$$ . These lower bounds are sharp and much better than for instance the bound that can be obtained from application of the Chebyshev inequality. In case $${\xi = 1}$$ Van Zuijlen solved this problem in [5]. We remark that our bound will have nice applications in probability theory and especially in random walk theory (cf. [1, 2]).
PubDate: 2017-05-11
DOI: 10.1007/s00026-017-0351-3

• Generalized Polarization Modules
• Authors: Héctor Blandin
Abstract: This work enrols the research line of M. Haiman on the Operator Theorem (the former Operator Conjecture). Given a $${\mathfrak{S}_n}$$ -stable family F of homogeneous polynomials in the variables $${x_i j}$$ with $${1 \leq i \leq \ell}$$ and $${1 \leq j \leq n}$$ . We define the polarization module generated by the family F, as the smallest vector space closed under taking partial derivatives and closed under the action of polarization operators that contains F. These spaces are representations of the direct product $${\mathfrak{S}_n \times GL_\ell(\mathbb{C})}$$ . We compute the graded Frobenius characteristic of these modules. We use some basic tools to study these spaces and give some in-depth calculations of low degree examples of a family or a single symmetric polynomial.
PubDate: 2017-04-28
DOI: 10.1007/s00026-017-0350-4

• Polyhedral Omega: a New Algorithm for Solving Linear Diophantine Systems
• Authors: Felix Breuer; Zafeirakis Zafeirakopoulos
Abstract: Polyhedral Omega is a new algorithm for solving linear Diophantine systems (LDS), i.e., for computing a multivariate rational function representation of the set of all non-negative integer solutions to a system of linear equations and inequalities. Polyhedral Omegacombines methods from partition analysis with methods from polyhedral geometry. In particular, we combine MacMahon’s iterative approach based on the Omega operator and explicit formulas for its evaluation with geometric tools such as Brion decompositions and Barvinok’s short rational function representations. In this way, we connect two recent branches of research that have so far remained separate, unified by the concept of symbolic cones which we introduce. The resulting LDS solver Polyhedral Omegais significantly faster than previous solvers based on partition analysis and it is competitive with state-of-the-art LDS solvers based on geometric methods. Most importantly, this synthesis of ideas makes Polyhedral Omegathe simplest algorithm for solving linear Diophantine systems available to date. Moreover, we provide an illustrated geometric interpretation of partition analysis, with the aim of making ideas from both areas accessible to readers from a wide range of backgrounds.
PubDate: 2017-04-26
DOI: 10.1007/s00026-017-0349-x

• New Non-existence Proofs for Ovoids of Hermitian Polar Spaces and
• Authors: John Bamberg; Jan De Beule; Ferdinand Ihringer
Abstract: We provide new proofs for the non-existence of ovoids in hyperbolic spaces of rank at least four in even characteristic, and for the Hermitian polar space H(5,4). We also improve the results of A. Klein on the non-existence of ovoids of Hermitian spaces and hyperbolic quadrics.
PubDate: 2017-02-10
DOI: 10.1007/s00026-017-0346-0

• On the Hamiltonicity of Triple Systems with High Minimum Degree
• Authors: Vojtěch Rödl; Andrzej Ruciński; Mathias Schacht; Endre Szemerédi
Abstract: We show that every 3-uniform hypergraph with minimum vertex degree at least 0.8 $$\left(\begin{array}{c}n-1\\2\end{array}\right)$$ contains a tight Hamiltonian cycle.
PubDate: 2017-02-09
DOI: 10.1007/s00026-017-0345-1

• On t -Core Towers and t -Defects of Partitions
• Authors: Larry Rolen
Abstract: We study generating functions which count the sizes of t-cores of partitions, and, more generally, the sizes of higher rows in t-core towers. We then use these results to derive an asymptotic results for the average size of the t-defect of partitions, as well as some curious congruences.
PubDate: 2017-02-03
DOI: 10.1007/s00026-017-0343-3

• Completely Effective Error Bounds for Stirling Numbers of the First and
Second Kinds via Poisson Approximation
• Authors: Richard Arratia; Stephen DeSalvo
Abstract: We provide completely effective error estimates for Stirling numbers of the first and second kinds, denoted by s(n, m) and S(n, m), respectively. These bounds are useful for values of $${m\geq n-O(\sqrt{n})}$$ . An application of our Theorem 3.2 yields, for example, $$\begin{array}{ll}{s({10^{12}}, {10^{12}}-2 \times{10^6})/{10^{35664464}} \in [1.87669, 1.876982],}\\{S({10^{12}}, {10^{12}}-2 \times{10^6})/{10^{35664463}} \in [1.30121, 1.306975]}.\end{array}$$ The bounds are obtained via Chen-Stein Poisson approximation, using an interpretation of Stirling numbers as the number of ways of placing non-attacking rooks on a chess board. As a corollary to Theorem 3.2, summarized in Proposition 2.4, we obtain two simple and explicit asymptotic formulas, one for each of s(n, m) and S(n, m), for the parametrization $${m = n-t {n^a}, 0 \leq a \leq \frac{1}{2}}$$ . These asymptotic formulas agree with the ones originally observed by Moser and Wyman in the range $${0 < a < \frac{1}{2}}$$ , and they connect with a recent asymptotic expansion by Louchard for $${\frac{1}{2} < a < 1}$$ , hence filling the gap at $${a = \frac{1}{2}}$$ . We also provide a generalization applicable to rook and file numbers.
PubDate: 2017-02-03
DOI: 10.1007/s00026-017-0339-z

• On the Convergence of Monotone Hurwitz Generating Functions
• Authors: I. P. Goulden; Mathieu Guay-Paquet; Jonathan Novak
Abstract: Monotone Hurwitz numbers were introduced by the authors as a combinatorially natural desymmetrization of the Hurwitz numbers studied in enumerative algebraic geometry. Over the course of several papers, we developed the structural theory of monotone Hurwitz numbers and demonstrated that it is in many ways parallel to that of their classical counterparts. In this note, we identify an important difference between the monotone and classical worlds: fixed-genus generating functions for monotone double Hurwitz numbers are absolutely summable, whereas those for classical double Hurwitz numbers are not. This property is crucial for applications of monotone Hurwitz theory in analysis. We quantify the growth rate of monotone Hurwitz numbers in fixed genus by giving universal upper and lower bounds on the radii of convergence of their generating functions.
PubDate: 2017-02-02
DOI: 10.1007/s00026-017-0341-5

• Congruences for Powers of the Partition Function
• Authors: Madeline Locus; Ian Wagner
Abstract: Let $${p_{-t}}$$ (n) denote the number of partitions of n into t colors. In analogy with Ramanujan’s work on the partition function, Lin recently proved that $${{p_{-3}}(11n+7) \equiv 0}$$ (mod 11) for every integer n. Such congruences, those of the form $${{p_{-t}} (\ell n+a) \equiv 0}$$ (mod $${\ell}$$ ), were previously studied by Kiming and Olsson. If $${\ell \geq 5}$$ is prime and $${-t {\epsilon} \{\ell-1, \ell-3\}}$$ , then such congruences satisfy $${24a \equiv-t}$$ (mod $${\ell}$$ ). Inspired by Lin’s example, we obtain natural infinite families of such congruences. If $${\ell \equiv 2}$$ (mod 3) ( $${\ell \equiv 3}$$ (mod 4) and $${\ell \equiv 11}$$ (mod 12), respectively) is prime and $${r \in \{4, 8, 14\}}$$ ( $${r \in \{6, 10\}}$$ and r = 26, respectively), then for $${t = \ell s-r}$$ , where $${s \geq 0}$$ , we have that $${p_{-t}}(\ell n + \frac{r(\ell^{2}-1)}{24}-\ell\lfloor\frac{r(\ell^{2}-1)}{24\ell}\rfloor)\equiv0 \,\,({\rm mod} \ell).$$ Moreover, we exhibit infinite families where such congruences cannot hold.
PubDate: 2017-02-02
DOI: 10.1007/s00026-017-0342-4

• Skew Standard Domino Tableaux and Partial Motzkin Paths
• Authors: Ting-Yuan Cheng; Sen-Peng Eu; Tung-Shan Fu; Yi-Lin Lee
Abstract: In this paper, we establish a bijection between standard domino tableaux with at most three rows and partial Motzkin paths. Moreover, we establish a connection between skew standard domino tableaux with at most three rows and a variant of partial Motzkin paths within the nonnegative quadrant and enumerate such tableaux with n dominoes in terms of linear combinations of Motzkin numbers.
PubDate: 2017-02-02
DOI: 10.1007/s00026-017-0340-6

• Counting Derangements and Nash Equilibria
• Authors: Raimundas Vidunas
Abstract: The maximal number of totally mixed Nash equilibria in games of several players equals the number of block derangements, as proved by McKelvey and McLennan. On the other hand, counting the derangements is a well-studied problem. The numbers are identified as linearization coefficients for Laguerre polynomials. MacMahon derived a generating function for them as an application of his master theorem. This article relates the algebraic, combinatorial, and game-theoretic problems that were not connected before. New recurrence relations, hypergeometric formulas, and asymptotics for the derangement counts are derived. An upper bound for the total number of all Nash equilibria is given.
PubDate: 2017-02-02
DOI: 10.1007/s00026-017-0344-2

• Facets of the r -Stable ( n , k )-Hypersimplex
• Authors: Takayuki Hibi; Liam Solus
Pages: 815 - 829
Abstract: Let k, n, and r be positive integers with k < n and $${r \leq \lfloor \frac{n}{k} \rfloor}$$ . We determine the facets of the r-stable n, k-hypersimplex. As a result, it turns out that the r-stable n, k-hypersimplex has exactly 2n facets for every $${r < \lfloor \frac{n}{k} \rfloor}$$ . We then utilize the equations of the facets to study when the r-stable hypersimplex is Gorenstein. For every k > 0 we identify an infinite collection of Gorenstein r-stable hypersimplices, consequently expanding the collection of r-stable hypersimplices known to have unimodal Ehrhart $${\delta}$$ -vectors.
PubDate: 2016-12-01
DOI: 10.1007/s00026-016-0325-x
Issue No: Vol. 20, No. 4 (2016)

• Recurrences for Eulerian Polynomials of Type B and Type D
• Authors: Matthew Hyatt
Pages: 869 - 881
Abstract: We introduce new recurrences for the type B and type D Eulerian polynomials, and interpret them combinatorially. These recurrences are analogous to a well-known recurrence for the type A Eulerian polynomials. We also discuss their relationship to polynomials introduced by Savage and Visontai in connection to the real-rootedness of the corresponding Eulerian polynomials.
PubDate: 2016-12-01
DOI: 10.1007/s00026-016-0327-8
Issue No: Vol. 20, No. 4 (2016)

• Avoiding Monotone Chains in Fillings of Layer Polyominoes
• Authors: Mitch Phillipson; Catherine H. Yan
Pages: 883 - 897
Abstract: In this paper we give simple bijective proofs that the number of fillings of layer polyominoes with no northeast chains is the same as the number with no southeast chains. We consider 01-fillings and $${{\mathbb{N}}}$$ -fillings and prove the results for both strong chains where the smallest rectangle containing the chain is also in the polyomino, and for regular chains where only the corners of the smallest rectangle containing the chain are required to be in the polyomino.
PubDate: 2016-12-01
DOI: 10.1007/s00026-016-0326-9
Issue No: Vol. 20, No. 4 (2016)

• Inductively Free Multiderivations of Braid Arrangements
• Authors: Henning Conrad; Gerhard Röhrle
Abstract: The reflection arrangement of a Coxeter group is a well-known instance of a free hyperplane arrangement. In 2002, Terao showed that equipped with a constant multiplicity each such reflection arrangement gives rise to a free multiarrangement. In this note we show that this multiarrangment satisfies the stronger property of inductive freeness in case the Coxeter group is of type A.
PubDate: 2016-10-22
DOI: 10.1007/s00026-016-0335-8

• On the Distribution of the Number of Fixed Vectors for the Finite
Classical Groups
• Authors: Jason Fulman; Dennis Stanton
Abstract: Motivated by analogous results for the symmetric group and compact Lie groups, we study the distribution of the number of fixed vectors of a random element of a finite classical group. We determine the limiting moments of these distributions, and find exactly how large the rank of the group has to be in order for the moment to stabilize to its limiting value. The proofs require a subtle use of some q-series identities. We also point out connections with orthogonal polynomials.
PubDate: 2016-10-22
DOI: 10.1007/s00026-016-0336-7

• Semitotal Domination in Claw-Free Cubic Graphs
• Authors: Michael A. Henning; Alister J. Marcon
Abstract: In this paper, we continue the study of semitotal domination in graphs in [Discrete Math. 324, 13–18 (2014)]. A set $${S}$$ of vertices in $${G}$$ is a semitotal dominating set of $${G}$$ if it is a dominating set of $${G}$$ and every vertex in $${S}$$ is within distance 2 of another vertex of $${S}$$ . The semitotal domination number, $${{\gamma_{t2}}(G)}$$ , is the minimum cardinality of a semitotal dominating set of $${G}$$ . This domination parameter is squeezed between arguably the two most important domination parameters; namely, the domination number, $${\gamma (G)}$$ , and the total domination number, $${{\gamma_{t}}(G)}$$ . We observe that $${\gamma (G) \leq {\gamma_{t2}}(G) \leq {\gamma_{t}}(G)}$$ . A claw-free graph is a graph that does not contain $${K_{1, \, 3}}$$ as an induced subgraph. We prove that if $${G}$$ is a connected, claw-free, cubic graph of order $${n \geq 10}$$ , then $${{\gamma_{t2}}(G) \leq 4n/11}$$ .
PubDate: 2016-10-12
DOI: 10.1007/s00026-016-0331-z

• A Bijection from Staircase Tableaux to Inversion Tables, Giving Some
Eulerian and Mahonian Statistics
• Authors: Sylvie Corteel; Sandrine Dasse-Hartaut
Abstract: We give a simple bijection between staircase tableaux and inversion tables. Some nice properties of the bijection allow us to easily compute the generating polynomials of subsets of the staircase tableaux. We also give a combinatorial interpretation of some statistics of these tableaux in terms of permutations.
PubDate: 2016-10-12
DOI: 10.1007/s00026-016-0329-6

JournalTOCs
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
Email: journaltocs@hw.ac.uk
Tel: +00 44 (0)131 4513762
Fax: +00 44 (0)131 4513327

Home (Search)
Subjects A-Z
Publishers A-Z
Customise
APIs