Another proof of Wilmes' conjecture

Another proof of the alternating sign matrix conjecture

Robbins conjectured, and Zeilberger recently proved, that there are 1!4!7!...(3n-2)!/n!/(n+1)!/.../(2n-1)! alternating sign matrices of order n. We give a new proof of this result using an analysis of the six-vertex state model (also called square ice) based on the Yang-Baxter equation.

关于哈德维格猜想的一个注记：每个4-色图都有$K_4$子式的另一种证明

A note on Hadwiger's conjecture: Another proof that every 4-chromatic graph has a $K_4$ minor

本文针对哈德维格猜想的第一个非平凡情形，给出一种新证明，通过利用图的子图的正常3-染色来构造$K_4$子式，从而证明每个色数至少为4的图都含有$K_4$子式。

Another refinement of the Bender-Knuth (ex-)Conjecture

We compute the generating function of column-strict plane partitions with parts in {1,2,...,n}, at most c columns, p rows of odd length and k parts equal to n. This refines both, Krattenthaler's ["The major counting of nonintersecting lattice paths and generating functions for tableaux", Mem. Amer. Math. Soc. 115 (1995)] and the author's ["A method for proving polynomial enumeration formulas", preprint] refinement of the Bender-Knuth (ex-)Conjecture. The result is proved by an extension of the method for proving polynomial enumeration formulas which was introduced by the author to q-quasi-poly…

关于图中零强迫与控制的TxGraffiti的另一个猜想

Another conjecture of TxGraffiti concerning zero forcing and domination in graphs

本文证明了TxGraffiti人工智能程序生成的猜想，即连通、三次且无爪图的零强迫数$Z(G)$不超过控制数$γ(G)$加2，并给出了达到该界的图的完整刻画，改进了已知上界。

另一种交替符号矩阵的双重细化计数

Yet another doubly refined enumeration of Alternating Sign Matrices

本文通过引入三个参数重新审视交替符号矩阵的双重细化计数，并推导出新的行列式公式，同时改进了分解猜想。

Spiral Chains: The Proofs of Tait's and Tutte's Three-Edge-Coloring Conjectures

In this paper we have shown without assuming the four color theorem of planar graphs that every (bridgeless) cubic planar graph has a three-edge-coloring. This is an old-conjecture due to Tait in the squeal of efforts in settling the four-color conjecture at the end of the 19th century. We have also shown the applicability of our method to another well-known three edge-coloring conjecture on cubic graphs. Namely Tutte's conjecture that "every 2-connected cubic graph with no Petersen minor is 3-edge colorable". Hence the conclusion of this paper implies another non-computer proof of the four co…

Proof of Andrews' conjecture on a_4ϕ_3 summation

We give a new proof of a_4ϕ_3 summation due to G.E. Andrews and confirm another_4ϕ_3 summation conjectured by him recently. Some variations of these two_4ϕ_3 summations are also given.

A counterexample to a conjecture of Björner and Lovász on the $χ$-coloring complex

Associated with every graph $G$ of chromatic number $χ$ is another graph $G'$. The vertex set of $G'$ consists of all $χ$-colorings of $G$, and two $χ$-colorings are adjacent when they differ on exactly one vertex. According to a conjecture of Björner and Lovász, this graph $G'$ must be disconnected. In this note we give a counterexample to this conjecture.

A proof of Ringel's Conjecture

A typical decomposition question asks whether the edges of some graph $G$ can be partitioned into disjoint copies of another graph $H$. One of the oldest and best known conjectures in this area, posed by Ringel in 1963, concerns the decomposition of complete graphs into edge-disjoint copies of a tree. It says that any tree with $n$ edges packs $2n+1$ times into the complete graph $K_{2n+1}$. In this paper, we prove this conjecture for large $n$.

Combinatorial proofs and generalizations of conjectures related to Euler's partition theorem

In a recent work, Andrews gave analytic proofs of two conjectures concerning some variations of two combinatorial identities between partitions of a positive integer into odd parts and partitions into distinct parts discovered by Beck. Subsequently, using the same method as Andrews, Chern presented the analytic proof of another Beck's conjecture relating the gap-free partitions and distinct partitions with odd length. However, the combinatorial interpretations of these conjectures are still unclear and required. In this paper, motivated by Glaisher's bijection, we give the combinatorial proofs…

Another proof of the $n!$ conjecture

The "n! conjecture" of Garsia and Haiman has inspired mathematicians for nearly two decades, even after Haiman published a proof in 2001. Kumar and Funch Thomsen proved in 2003 that in order to prove the conjecture for all partitions, it suffices to prove it for the so-called "staircase partitions" $(k,k-1,...,2,1)$ for each $k>1$. In the present paper we give a construction of a specially designed two-dimensional family of length-$n$ subschemes of the plane, and use that to prove the $n!$ conjecture for staircase partitions. Together with the result of Kumar and Funch Thomsen, this provides a…

关于旋转兼容平面覆盖结果的另一个证明

Another proof of the result on rotation compatible planar covers

本文通过基于基图中生成树的结构分析，给出了旋转兼容平面覆盖定理的一个组合证明。

Maximizing spectral radius and number of spanning trees in bipartite graphs

The problems of maximizing the spectral radius and the number of spanning trees in a class of bipartite graphs with certain degree constraints are considered. In both the problems, the optimal graph is conjectured to be a Ferrers graph. Known results towards the resolution of the conjectures are described. We give yet another proof of a formula due to Ehrenborg and van Willigenburg for the number of spanning trees in a Ferrers graph. The main tool is a result which gives several necessary and sufficient conditions under which the removal of an edge in a graph does not affect the resistance dis…

Proof of a conjecture of Matherne, Morales, and Selover on encodings of unit interval orders

There are two bijections from unit interval orders on $n$ elements to Dyck paths from $(0,0)$ to $(n,n)$. One is to consider the pairs of incomparable elements, which form the set of boxes between some Dyck path and the diagonal. Another is to find a particular part listing (in the sense of Guay-Paquet) which yields an isomorphic poset, and to interpret the part listing as the area sequence of a Dyck path. Matherne, Morales, and Selover conjectured that, for any unit interval order, these two Dyck paths are related by Haglund's well-known zeta bijection. In this paper we prove their conjecture…

墙中另一块砖：计算辅助证明Thrackle的改进上界

Another Brick in the Wall: A Computationally Assisted Proof of an Improved Upper Bound for Thrackles

该研究通过改进Fulek与Pach的算法，计算证明关键哑铃图非Thrackle可实现，结合Xu的框架及相关论证，将Thrackle边数上界改进为n≥4时m≤1.385(n-1)。

A symmetric function generalization of the Zeilberger--Bressoud $q$-Dyson theorem

In 2000, Kadell gave an orthogonality conjecture for a symmetric function generalization of the Zeilberger--Bressoud $q$-Dyson theorem or the $q$-Dyson constant term identity. This conjecture was proved by Károlyi, Lascoux and Warnaar in 2015. In this paper, by slightly changing the variables of Kadell's conjecture, we obtain another symmetric function generalization of the $q$-Dyson constant term identity. This new generalized constant term admits a simple product-form expression.

From Bruhat intervals to intersection lattices and a conjecture of Postnikov

We prove the conjecture of A. Postnikov that (A) the number of regions in the inversion hyperplane arrangement associated with a permutation $w\in \Sn$ is at most the number of elements below $w$ in the Bruhat order, and (B) that equality holds if and only if $w$ avoids the patterns 4231, 35142, 42513 and 351624. Furthermore, assertion (A) is extended to all finite reflection groups. A byproduct of this result and its proof is a set of inequalities relating Betti numbers of complexified inversion arrangements to Betti numbers of closed Schubert cells. Another consequence is a simple combinator…

A new proof of Andrews' conjecture for $_4ϕ_3$-series

In terms of Sear's transformation formula for $_4ϕ_3$-series, we give new proofs of a summation formula for ${_4ϕ_3}$-series due to Andrews [2] and another summation formula for${_4ϕ_3}$-series conjectured in the same paper. Meanwhile, other several related results are also derived.

Yet another proof of Szemeredi's theorem

Using the density-increment strategy of Roth and Gowers, we derive Szemeredi's theorem on arithmetic progressions from the inverse conjectures GI(s) for the Gowers norms, recently established by the authors and Ziegler.

The sensitivity conjecture, induced subgraphs of cubes, and Clifford algebras

We give another version of Huang's proof that an induced subgraph of the n-dimensional cube graph containing over half the vertices has maximal degree at least $\sqrt{n}$, which implies the Sensitivity Conjecture. This argument uses Clifford algebras of positive definite signature in a natural way. We also prove a weighted version of the result.

A note on Makeev's conjectures

A counterexample is given for the Knaster-like conjecture of Makeev for functions on $S^2$. Some particular cases of another conjecture of Makeev, on inscribing a quadrangle into a smooth simple closed curve, are solved positively.

Proof of a conjecture involving Sun polynomials

The Sun polynomials $g_n(x)$ are defined by \begin{align*} g_n(x)=\sum_{k=0}^n{n\choose k}^2{2k\choose k}x^k. \end{align*} We prove that, for any positive integer $n$, there hold \begin{align*} &\frac{1}{n}\sum_{k=0}^{n-1}(4k+3)g_k(x) \in\mathbb{Z}[x],\quad\text{and}\\ &\sum_{k=0}^{n-1}(8k^2+12k+5)g_k(-1)\equiv 0\pmod{n}. \end{align*} The first one confirms a recent conjecture of Z.-W. Sun, while the second one partially answers another conjecture of Z.-W. Sun. We give three different proofs of the former. One of them depends on the following congruence: $$ {m+n-2\choose m-1}{n\choose m}{2n\ch…

The proof of the $l^2$ Decoupling Conjecture

We prove the $l^2$ Decoupling Conjecture for compact hypersurfaces with positive definite second fundamental form and also for the cone. This has a wide range of important consequences. One of them is the validity of the Discrete Restriction Conjecture, which (up to $N^ε$ losses) implies the full range of expected $L^p_{x,t}$ Strichartz estimates for both classical and irrational tori. Another one is an improvement in the range for the discrete restriction theory for lattice points on the sphere. Various applications in Additive Combinatorics, Incidence Geometry and Number Theory are also disc…