In this paper, we study two kinds of combinatorial objects, generalized integer partitions and tilings of two dimensional zonotopes, using dynamical systems and order theory. We show that the sets of partitions ordered with a simple dynamics, have the distributive lattice structure. Likewise, we show that the set of tilings of zonotopes, ordered with a simple and classical dynamics, is the disjoint union of distributive lattices which we describe. We also discuss the special case of linear integer partitions, for which other dynamical systems exist. These results give a better understanding of the behaviour of tilings of zonotopes with flips and dynamical systems involving partitions.
Integer compositions, integer partitions, Fibonacci numbers, and generalizations of these have recently been shown to be interconnected via two-toned tilings of horizontal grids. In this article, we present refinements of two-toned tilings, describe functions which analyze them, and apply these to generalizations of integer compositions and partitions which interpolate between the two.
We study the weighted partition function for lozenge tilings, with weights given by multivariate rational functions originally defined by Morales, Pak and Panova (2019) in the context of the factorial Schur functions. We prove that this partition function is symmetric for large families of regions. We employ both combinatorial and algebraic proofs.
MacMahon's theorem on plane partitions yields a simple product formula for tiling number of a hexagon, and Cohn, Larsen and Propp's theorem provides an explicit enumeration for tilings of a dented semihexagon via semi-strict Gelfand--Tsetlin patterns. In this paper, we prove a natural hybrid of the two theorems for hexagons with an arbitrary set of unit triangles removed along a horizontal axis. In particular, we show that the `shuffling' of removed unit triangles only changes the tiling number of the region by a simple multiplicative factor. Our main result generalizes a number of known enume…
We prove that for all integers $Δ,r \geq 2$, there is a constant $C = C(Δ,r) >0$ such that the following is true for every sequence $\mathcal{F} = \{F_1, F_2, \ldots\}$ of graphs with $v(F_n) = n$ and $Δ(F_n) \leq Δ$, for each $n \in \mathbb{N}$. In every $r$-edge-coloured $K_n$, there is a collection of at most $C$ monochromatic copies from $\mathcal{F}$ whose vertex-sets partition $V(K_n)$. This makes progress on a conjecture of Grinshpun and Sárközy.
We define and study noncommutative crossing partitions which are a generalization of non-crossing partitions. By introducing a new cover relation on binary trees, we show that the partially ordered set of noncommutative crossing partitions is a graded lattice. This new lattice contains the Kreweras lattice, the lattice of non-crossing partitions, as a sublattice. We calculate the Möbius function, the number of maximal chains and the number of $k$-chains in this new lattice by constructing an explicit $EL$-labeling on the lattice. By use of the $EL$-labeling, we recover the classical results on…
Representation theory of the symmetric group $\mathfrak{S}_n$ has a very distinctive combinatorial flavor. The conjugacy classes as well as the irreducible characters are indexed by integer partitions $λ\vdash n$. We introduce class functions on $\mathfrak{S}_n$ that count the number of certain tilings of Young diagrams. The counting interpretation gives a uniform expression of these class functions in the ring of character polynomials, as defined by \cite{murnaghanfirst}. A modern treatment of character polynomials is given in \cite{orellana-zabrocki}. We prove a relation between these combin…
Enumerations of lozenge tilings, lattice paths, and perfect matchings and the weak Lefschetz property
MacMahon列举了$a \times b \times c$框中的平面分区。这些是在双射菱形平铺的六边形,某些完美的匹配,和家庭的非交叉晶格路径。在这项工作中,我们考虑更一般的区域,称为三角区域,并建立后三个双射的有符号版本。事实上,我们使用完美匹配和家庭的不相交的晶格路径来定义两个符号的菱形瓷砖。一个组合的论点,涉及一个新的方法,所谓的解决方案的穿刺,然后表明,这些迹象实际上是等价的。这特别提供了这些族的两个不同的行列式枚举。利用这些结果研究了三维多项式环的单项式理想的Artin行列式的弱Lefschetz性质.建立了理想的合丛具有弱Lefschetz性质和半稳定性的充分条件,对具有弱Lefschetz性质的二型代数进行了分类,并深入研究了单项几乎完全交.此外,我们开发了一个通用的方法,往往与代数失败的弱Lefschetz属性复曲面,满足拉普拉斯方程。我们还提出了复曲面品种,满足任意多个拉普拉斯方程的例子。我们的组合方法使我们能够解决依赖于我们的许多结果的基本字段的特性。