{"title":"Completing the Asymptotic Classification of Mostly Symmetric Short Step Walks in an Orthant","authors":"Alexander Kroitor, Stephen Melczer","doi":"10.1007/s00026-024-00739-6","DOIUrl":"10.1007/s00026-024-00739-6","url":null,"abstract":"<div><p>In recent years, the techniques of analytic combinatorics in several variables (ACSV) have been applied to determine asymptotics for several families of lattice path models restricted to the orthant <span>({mathbb {N}}^d)</span> and defined by step sets <span>({mathcal {S}}subset {-1,0,1}^dsetminus {textbf{0}})</span>. Using the theory of ACSV for smooth singular sets, Melczer and Mishna determined asymptotics for the number of walks in any model whose set of steps <span>({mathcal {S}})</span> is ‘highly symmetric’ (symmetric over every axis). Building on this work, Melczer and Wilson determined asymptotics for all models where <span>({mathcal {S}})</span> is ‘mostly symmetric’ (symmetric over all but one axis) <i>except</i> for models whose set of steps have a vector sum of zero but are not highly symmetric. In this paper, we complete the asymptotic classification of the mostly symmetric case by analyzing a family of saddle-point-like integrals whose amplitudes are singular near their saddle points.</p></div>","PeriodicalId":50769,"journal":{"name":"Annals of Combinatorics","volume":"29 2","pages":"575 - 599"},"PeriodicalIF":0.7,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145167193","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"From Hodge Theory for Tame Functions to Ehrhart Theory for Polytopes","authors":"Antoine Douai","doi":"10.1007/s00026-024-00738-7","DOIUrl":"10.1007/s00026-024-00738-7","url":null,"abstract":"<div><p>We study the interplay between Sabbah’s mixed Hodge structure for tame regular functions and Ehrhart theory for polytopes. We first analyze the Poincaré polynomial of the Hodge filtration of this mixed Hodge structure (we call this Poincaré polynomial the <span>(theta )</span>-vector). Using the symmetry of the Hodge numbers involved, we show that it shares many properties with the <span>(h^*)</span>-vector of a polytope. For instance, we define from the <span>(theta )</span>-vector the Hodge–Ehrhart polynomial of a general tame function and we show that it satisfies a reciprocity law, analogous to the one satisfied by the Ehrhart polynomial of a polytope. We study the roots of this Hodge–Ehrhart polynomial, in particular their distribution around some critical lines. Using techniques coming from singularity theory, we also show a Thom–Sebastiani type theorem for the <span>(theta )</span>-vector. Finally, we offer some linear inequalities among the coefficients of the <span>(theta )</span>-vectors which could be helpful to test if a polynomial is a <span>(theta )</span>-vector or not. In the very particular case of convenient and nondegenerate Laurent polynomials, we show (using the Brieskorn lattice and the <i>V</i>-filtration) that the previous results agree with the classical ones in combinatorics and we emphasize various combinatorial properties of Sabbah’s Hodge numbers: on the way, this provides an alternative interpretation of prior results about the (limit) Hodge numbers of hypersurfaces in a torus obtained in a different framework by Danilov–Khovanskiĭ and more recently by Katz–Stapledon.</p></div>","PeriodicalId":50769,"journal":{"name":"Annals of Combinatorics","volume":"29 4","pages":"1077 - 1107"},"PeriodicalIF":0.7,"publicationDate":"2024-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145435846","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Local Limit Theorems for Hook Lengths in Partitions","authors":"Tapas Bhowmik, Wei-Lun Tsai","doi":"10.1007/s00026-024-00737-8","DOIUrl":"10.1007/s00026-024-00737-8","url":null,"abstract":"<div><p>Partition hook lengths have wide-ranging applications in combinatorics, number theory, physics, and representation theory. We study two infinite families of random variables associated with <i>t</i>-hooks. For fixed <span>(tge 1,)</span> if <span>(Y_{t;,n})</span> counts the number of hooks of length <i>t</i> in a random integer partition of <i>n</i>, we prove a uniform local limit theorem for <span>(Y_{t;,n})</span> on any bounded set of <span>({mathbb {R}}.)</span> To achieve this, we establish an asymptotic formula with a power-saving error term for the number of partitions of <i>n</i> with <i>m</i> many <i>t</i>-hooks. In contrast, we define <span>({widehat{Y}}_{t;,n})</span> as the count of hooks divisible by <i>t</i> in a randomly chosen partition of <i>n</i>. While <span>({widehat{Y}}_{t;,n})</span> converges in distribution, we show that it fails to satisfy the local limit theorem for any <span>(t ge 2)</span>. The proofs employ the multivariable saddle-point method, asymptotic formulas for the number of <i>t</i>-core partitions from Anderson and Lulov–Pittel, and estimates of certain exponential sums. Notably, for <span>(t=4,)</span> the analysis involves the asymptotic behavior of class numbers of imaginary quadratic fields.</p></div>","PeriodicalId":50769,"journal":{"name":"Annals of Combinatorics","volume":"29 3","pages":"853 - 884"},"PeriodicalIF":0.7,"publicationDate":"2024-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00026-024-00737-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145037274","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Special Functions for Hyperoctahedral Groups Using Bosonic Lattice Models","authors":"Ben Brubaker, Will Grodzicki, Andrew Schultz","doi":"10.1007/s00026-024-00734-x","DOIUrl":"10.1007/s00026-024-00734-x","url":null,"abstract":"<div><p>Recent works have sought to realize certain families of orthogonal, symmetric polynomials as partition functions of well-chosen classes of solvable lattice models. Many of these use Boltzmann weights arising from the trigonometric six-vertex model <i>R</i>-matrix (or generalizations or specializations of these weights). In this paper, we seek new variants of bosonic models on lattices designed for Cartan type <i>C</i> root systems, whose partition functions match the zonal spherical function in type <i>C</i>. Under general assumptions, we find that this is possible for all highest weights in rank two and three, but not for higher rank. In ranks two and three, this may be regarded as a new generating function formula for zonal spherical functions (also known as Hall–Littlewood polynomials) in type <i>C</i>.</p></div>","PeriodicalId":50769,"journal":{"name":"Annals of Combinatorics","volume":"29 2","pages":"491 - 539"},"PeriodicalIF":0.7,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145164094","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"On Partitions with Bounded Largest Part and Fixed Integral GBG-rank Modulo Primes","authors":"Alexander Berkovich, Aritram Dhar","doi":"10.1007/s00026-024-00733-y","DOIUrl":"10.1007/s00026-024-00733-y","url":null,"abstract":"<div><p>In 2009, Berkovich and Garvan introduced a new partition statistic called the GBG-rank modulo <i>t</i> which is a generalization of the well-known BG-rank. In this paper, we use the Littlewood decomposition of partitions to study partitions with bounded largest part and the fixed integral value of GBG-rank modulo primes. As a consequence, we obtain new elegant generating function formulas for unrestricted partitions, self-conjugate partitions, and partitions whose parts repeat a finite number of times.\u0000</p></div>","PeriodicalId":50769,"journal":{"name":"Annals of Combinatorics","volume":"29 4","pages":"1063 - 1076"},"PeriodicalIF":0.7,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145435845","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Michał Dȩbski, Jarosław Grytczuk, Bartłomiej Pawlik, Jakub Przybyło, Małgorzata Śleszyńska-Nowak
{"title":"Words Avoiding Tangrams","authors":"Michał Dȩbski, Jarosław Grytczuk, Bartłomiej Pawlik, Jakub Przybyło, Małgorzata Śleszyńska-Nowak","doi":"10.1007/s00026-024-00736-9","DOIUrl":"10.1007/s00026-024-00736-9","url":null,"abstract":"<div><p>A <i>tangram</i> is a word in which every letter occurs an even number of times. Such word can be cut into parts that can be arranged into two identical words. The minimum number of cuts needed is called the <i>cut number</i> of a tangram. For example, the word <img> is a tangram with cut number one, while the word <img> is a tangram with cut number two. Clearly, tangrams with cut number one coincide with the well-known family of words, known as <i>squares</i>, having the form <i>UU</i> for some nonempty word <i>U</i>. A word <i>W</i> <i>avoids</i> a word <i>T</i> if it is not possible to write <span>(W=ATB)</span>, for any words <i>A</i> and <i>B</i> (possibly empty). The famous 1906 theorem of Thue asserts that there exist arbitrarily long words avoiding squares over an alphabet with just <i>three</i> letters. Given a fixed number <span>(kgeqslant 1)</span>, how many letters are needed to avoid tangrams with the cut number at most <i>k</i>? Let <i>t</i>(<i>k</i>) denote the minimum size of an alphabet needed for that purpose. By Thue’s result we have <span>(t(1)=3)</span>, which easily implies <span>(t(2)=3)</span>. Curiously, these are currently the only known exact values of this function. In our main result we prove that <span>(t(k)=Theta (log _2k))</span>. The proof uses <i>entropy compression</i> argument and <i>Zimin words</i>. Using a different method we prove that <span>(t(k)leqslant k+1)</span> for all <span>(kgeqslant 4)</span>, which gives more exact estimates for small values of <i>k</i>. The proof makes use of <i>Dejean words</i> and a curious property of <i>Gauss words</i>, which is perhaps of independent interest.</p></div>","PeriodicalId":50769,"journal":{"name":"Annals of Combinatorics","volume":"29 3","pages":"905 - 920"},"PeriodicalIF":0.7,"publicationDate":"2024-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00026-024-00736-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145037268","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Planar Binary Trees, Noncrossing Partitions and the Operator-Valued S-Transform","authors":"Kurusch Ebrahimi-Fard, Timothé Ringeard","doi":"10.1007/s00026-024-00730-1","DOIUrl":"10.1007/s00026-024-00730-1","url":null,"abstract":"<div><p>We revisit the twisted multiplicativity property of Voiculescu’s S-transform in the operator-valued setting, using a specific bijection between planar binary trees and noncrossing partitions.</p></div>","PeriodicalId":50769,"journal":{"name":"Annals of Combinatorics","volume":"29 3","pages":"799 - 836"},"PeriodicalIF":0.7,"publicationDate":"2024-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00026-024-00730-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145037419","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Two-Face Complete Regular Dessins","authors":"Yuanyuan Chen, Wenwen Fan, Li Ma","doi":"10.1007/s00026-024-00735-w","DOIUrl":"10.1007/s00026-024-00735-w","url":null,"abstract":"<div><p>A <i>complete dessin</i> is an orientable map with underlying graph being a complete bipartite graph, which is said to be <i>regular</i> if its group of color- and orientation-preserving automorphisms acts regularly on the edges. This paper presents a classification and enumeration of complete regular dessins that have exactly two faces, which is not only a generalization of uniface regular dessins (see Fan et al. in J Algebr Comb 49:125–134, 2019) and planar two-face maps (see Bousquet et al. in Discrete Math 222:1–25, 2000), but also a special case of the classification of complete regular dessins proposed by Jones.</p></div>","PeriodicalId":50769,"journal":{"name":"Annals of Combinatorics","volume":"29 4","pages":"1045 - 1061"},"PeriodicalIF":0.7,"publicationDate":"2024-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145435939","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"General Position Sets, Colinear Sets, and Sierpiński Product Graphs","authors":"Jing Tian, Sandi Klavžar","doi":"10.1007/s00026-024-00732-z","DOIUrl":"10.1007/s00026-024-00732-z","url":null,"abstract":"<div><p>Let <span>(G otimes _f H)</span> denote the Sierpiński product of graphs <i>G</i> and <i>H</i> with respect to the function <i>f</i>. The Sierpiński general position number <span>(textrm{gp}{_{textrm{S}}}(G,H))</span> is introduced as the cardinality of a largest general position set in <span>(G otimes _f H)</span> over all possible functions <i>f</i>. Similarly, the lower Sierpiński general position number <span>(underline{textrm{gp}}{_{textrm{S}}}(G,H))</span> is the corresponding smallest cardinality. The concept of vertex-colinear sets is introduced. Bounds for the general position number in terms of extremal vertex-colinear sets, and bounds for the (lower) Sierpiński general position number are proved. The extremal graphs are investigated. Formulas for the (lower) Sierpiński general position number of the Sierpiński products with <span>(K_2)</span> as the first factor are deduced. It is proved that if <span>(m,nge 2)</span>, then <span>(textrm{gp}{_{textrm{S}}}(K_m,K_n) = m(n-1))</span>, and that if <span>(nge 2,m-2)</span>, then <span>(underline{textrm{gp}}{_{textrm{S}}}(K_m,K_n) = m(n-m+1))</span>.</p></div>","PeriodicalId":50769,"journal":{"name":"Annals of Combinatorics","volume":"29 3","pages":"837 - 852"},"PeriodicalIF":0.7,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145037314","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Totally Symmetric Self-Complementary Plane Partition Matrices and Related Polytopes","authors":"Vincent Holmlund, Jessica Striker","doi":"10.1007/s00026-024-00723-0","DOIUrl":"10.1007/s00026-024-00723-0","url":null,"abstract":"<div><p>Plane partitions in the totally symmetric self-complementary symmetry class (TSSCPPs) are known to be equinumerous with <span>(ntimes n)</span> alternating sign matrices, but no explicit bijection is known. In this paper, we give a bijection from these plane partitions to <span>({0,1,-1})</span>-matrices we call magog matrices, some of which are alternating sign matrices. We explore enumerative properties of these matrices related to natural statistics such as inversion number and number of negative ones. We then investigate the polytope defined as their convex hull. We show that all the magog matrices are extreme and give a partial inequality description. Finally, we define another TSSCPP polytope as the convex hull of TSSCPP boolean triangles and determine its dimension, inequalities, vertices, and facets.</p></div>","PeriodicalId":50769,"journal":{"name":"Annals of Combinatorics","volume":"29 3","pages":"761 - 798"},"PeriodicalIF":0.7,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00026-024-00723-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145037444","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}