Reflections on symmetric polynomials and arithmetic functions

On arithmetic progressions in symmetric sets in finite field model

We consider two problems regarding arithmetic progressions in symmetric sets in the finite field (product space) model. First, we show that a symmetric set $S\subseteq\mathbb{Z}_q^n$ containing $|S|=μ\cdot q^n$ elements must contain at least $δ(q,μ)\cdot q^n\cdot 2^n$ arithmetic progressions $x,x+d,\ldots,x+(q-1)\cdot d$ such that the difference $d$ is restricted to lie in $\{0,1\}^n$. Second, we show that for prime $p$ a symmetric set $S\subseteq\mathbb{F}^n_p$ with $|S|=μ\cdot p^n$ elements contains at least $μ^{C(p)}\cdot p^{2n}$ arithmetic progressions of length $p$. This establishes that …

Arithmetic partition sums and orbits of Z_n^k under the symmetric group S_k

We study M(n,k,r), the number of orbits of {(a_1,...,a_k)\in Z_n^k | a_1+...+a_k = r (mod n)} under the action of S_k. Equivalently, M(n,k,r) sums the partition numbers of an arithmetic sequence: M(n,k,r) = sum_{t \geq 0} p(n-1,k,r+nt), where p(a,b,t) denotes the number of partitions of t into at most b parts, each of which is at most a. We derive closed formulas and various identities for such arithmetic partition sums. These results have already appeared in Elashvili/Jibladze/Pataraia, Combinatorics of necklaces and "Hermite reciprocity", J. Alg. Combin. 10 (1999) 173-188, and the main resul…

构造具有反射对称性的图的柔性实现

Constructing reflection-symmetric flexible realisations of graphs

本文提出了一种基于边着色的条件，用于构造具有反射对称性的图的柔性实现，并研究了由三角形和平行四边形组成的特定反射对称性实现类别。

算术函数的矩阵方法

Matrix methods for arithmetic functions

本研究借鉴对称函数理论的思路将矩阵与算术函数关联，把矩阵方法应用于算术函数领域，并研究了关联矩阵的特征多项式，拓展了算术函数的研究方法。

Arithmetic aspects of symmetric edge polytopes

We investigate arithmetic, geometric and combinatorial properties of symmetric edge polytopes. We give a complete combinatorial description of their facets. By combining Gröbner basis techniques, half-open decompositions and methods for interlacing polynomials we provide an explicit formula for the $h^\ast$-polynomial in case of complete bipartite graphs. In particular, we show that the $h^\ast$-polynomial is $γ$-positive and real-rooted. This proves Gal's conjecture for arbitrary flag unimodular triangulations in this case, and, beyond that, we prove a strengthing due to Nevo and Petersen (20…

Motions of grid-like reflection frameworks

Combinatorial characterisations are obtained of symmetric and anti-symmetric infinitesimal rigidity for two-dimensional frameworks with reflectional symmetry in the case of norms where the unit ball is a quadrilateral and where the reflection acts freely on the vertex set. At the framework level, these characterisations are given in terms of induced monochrome subgraph decompositions, and at the graph level they are given in terms of sparsity counts and recursive construction sequences for the corresponding signed quotient graphs.