scholarly journals Crossings and Nestings in Colored Set Partitions

10.37236/3163 ◽  
2013 ◽  
Vol 20 (4) ◽  
Author(s):  
Eric Marberg
Keyword(s):  
Recent Work ◽  
Joint Distribution ◽  
Usual Sense ◽  
Set Partitions ◽  
Enumeration Problems ◽  
Motzkin Paths ◽  
Element Set

Chen, Deng, Du, Stanley, and Yan introduced the notion of $k$-crossings and $k$-nestings for set partitions, and proved that the sizes of the largest $k$-crossings and $k$-nestings in the partitions of an $n$-set possess a symmetric joint distribution. This work considers a generalization of these results to set partitions whose arcs are labeled by an $r$-element set (which we call $r$-colored set partitions). In this context, a $k$-crossing or $k$-nesting is a sequence of arcs, all with the same color, which form a $k$-crossing or $k$-nesting in the usual sense. After showing that the sizes of the largest crossings and nestings in colored set partitions likewise have a symmetric joint distribution, we consider several related enumeration problems. We prove that $r$-colored set partitions with no crossing arcs of the same color are in bijection with certain paths in $\mathbb{N}^r$, generalizing the correspondence between noncrossing (uncolored) set partitions and 2-Motzkin paths. Combining this with recent work of Bousquet-Mélou and Mishna affords a proof that the sequence counting noncrossing 2-colored set partitions is P-recursive. We also discuss how our methods extend to several variations of colored set partitions with analogous notions of crossings and nestings.

Joint distributions of successes, failures and patterns in enumeration problems

2000 ◽  
Vol 32 (3) ◽  
pp. 866-884 ◽  
Author(s):  
S Chadjiconstantinidis ◽  
D. L. Antzoulakos ◽  
M. V. Koutras
Keyword(s):  
Joint Distribution ◽  
Joint Probability ◽  
Fixed Number ◽  
Composite Pattern ◽  
Joint Distributions ◽  
Special Cases ◽  
Enumeration Problems ◽  
Binomial Type ◽  
Probability Mass ◽  
Mass Functions

Let ε be a (single or composite) pattern defined over a sequence of Bernoulli trials. This article presents a unified approach for the study of the joint distribution of the number Sn of successes (and Fn of failures) and the number Xn of occurrences of ε in a fixed number of trials as well as the joint distribution of the waiting time Tr till the rth occurrence of the pattern and the number STr of successes (and FTr of failures) observed at that time. General formulae are developed for the joint probability mass functions and generating functions of (Xn,Sn), (Tr,STr) (and (Xn,Sn,Fn),(Tr,STr,FTr)) when Xn belongs to the family of Markov chain imbeddable variables of binomial type. Specializing to certain success runs, scans and pattern problems several well-known results are delivered as special cases of the general theory along with some new results that have not appeared in the statistical literature before.

scholarly journals Arc-Coloured Permutations

2013 ◽  
Vol DMTCS Proceedings vol. AS,... (Proceedings) ◽  
Author(s):  
Lily Yen
Keyword(s):  
Generating Functions ◽  
Joint Distribution ◽  
Rational Functions ◽  
Set Partitions ◽  
Combinatorial Objects ◽  
Crossing Numbers ◽  
Rational Series ◽  
Nous Montrons ◽  
International Audience ◽  
Labelled Graphs

International audience The equidistribution of many crossing and nesting statistics exists in several combinatorial objects like matchings, set partitions, permutations, and embedded labelled graphs. The involutions switching nesting and crossing numbers for set partitions given by Krattenthaler, also by Chen, Deng, Du, Stanley, and Yan, and for permutations given by Burrill, Mishna, and Post involved passing through tableau-like objects. Recently, Chen and Guo for matchings, and Marberg for set partitions extended the result to coloured arc annotated diagrams. We prove that symmetric joint distribution continues to hold for arc-coloured permutations. As in Marberg's recent work, but through a different interpretation, we also conclude that the ordinary generating functions for all j-noncrossing, k-nonnesting, r-coloured permutations according to size n are rational functions. We use the interpretation to automate the generation of these rational series for both noncrossing and nonnesting coloured set partitions and permutations. <begin>otherlanguage*</begin>french L'équidistribution de plusieurs statistiques décrites en termes d'emboitements et de chevauchements d'arcs s'observes dans plusieurs familles d'objects combinatoires, tels que les couplages, partitions d'ensembles, permutations et graphes étiquetés. L'involution échangeant le nombre d'emboitements et de chevauchements dans les partitions d'ensemble due à Krattenthaler, et aussi Chen, Deng, Du, Stanley et Yan, et l'involution similaire dans les permutations due à Burrill, Mishna et Post, requièrent d'utiliser des objets de type tableaux. Récemment, Chen et Guo pour les couplages, et Marberg pour les partitions d'ensembles, ont étendu ces résultats au cas de diagrammes arc-annotés coloriés. Nous démontrons que la propriété d'équidistribution s'observe est aussi vraie dans le cas de permutations aux arcs coloriés. Tout comme dans le travail résent de Marberg, mais via un autre chemin, nous montrons que les séries génératrices ordinaires des permutations r-coloriées ayant au plus j chevauchements et k emboitements, comptées selon la taille n, sont des fonctions rationnelles. Nous décrivons aussi des algorithmes permettant de calculer ces fonctions rationnelles pour les partitions d'ensembles et les permutations coloriées sans emboitement ou sans chevauchement. <end>otherlanguage*</end>

scholarly journals Diagonal Asymptotics for Products of Combinatorial Classes

2014 ◽  
Vol 24 (1) ◽  
pp. 354-372
Author(s):  
MARK C. WILSON
Keyword(s):  
Joint Distribution ◽  
Supercritical Case ◽  
Riordan Arrays ◽  
Alternative Method ◽  
Enumeration Problems

We generalize and improve recent results by Bóna and Knopfmacher and by Banderier and Hitcz-enko concerning the joint distribution of the sum and number of parts in tuples of restricted compositions. Specifically, we generalize the problem to general combinatorial classes and relax the requirement that the sizes of the compositions be equal. We extend the main explicit results to enumeration problems whose counting sequences are Riordan arrays. In this framework, we give an alternative method for computing asymptotics in the supercritical case, which avoids explicit diagonal extraction.

scholarly journals Crossings and Nestings for Arc-Coloured Permutations and Automation

10.37236/4080 ◽  
2015 ◽  
Vol 22 (1) ◽  
Author(s):  
Lily Yen
Keyword(s):  
Generating Functions ◽  
Joint Distribution ◽  
Rational Functions ◽  
Set Partitions ◽  
Combinatorial Objects

Symmetric joint distribution between crossings and nestings was established in several combinatorial objects. Recently, Marberg extended Chen and Guo's result on coloured matchings to coloured set partitions following a multi-dimensional generalization of the bijection and enumerative methods from Chen, Deng, Du, Stanley, and Yan. We complete the study for arc-coloured permutations by establishing symmetric joint distribution for crossings and nestings and by showing that the ordinary generating functions for $j$-noncrossing, $k$-nonnesting, $r$-coloured permutations according to size $n$ are rational functions. Finally, we automate the generation of these rational functions and analyse the first $70$ series.

Joint distributions of successes, failures and patterns in enumeration problems

2000 ◽  
Vol 32 (03) ◽  
pp. 866-884 ◽  
Author(s):  
S Chadjiconstantinidis ◽  
D. L. Antzoulakos ◽  
M. V. Koutras
Keyword(s):  
Joint Distribution ◽  
Joint Probability ◽  
Fixed Number ◽  
Composite Pattern ◽  
Joint Distributions ◽  
Special Cases ◽  
Enumeration Problems ◽  
Binomial Type ◽  
Probability Mass ◽  
Mass Functions

Let ε be a (single or composite) pattern defined over a sequence of Bernoulli trials. This article presents a unified approach for the study of the joint distribution of the number S n of successes (and F n of failures) and the number X n of occurrences of ε in a fixed number of trials as well as the joint distribution of the waiting time T r till the rth occurrence of the pattern and the number S T r of successes (and F T r of failures) observed at that time. General formulae are developed for the joint probability mass functions and generating functions of (X n ,S n ), (T r ,S T r ) (and (X n ,S n ,F n ),(T r ,S T r ,F T r )) when X n belongs to the family of Markov chain imbeddable variables of binomial type. Specializing to certain success runs, scans and pattern problems several well-known results are delivered as special cases of the general theory along with some new results that have not appeared in the statistical literature before.

scholarly journals $k$-distant crossings and nestings of matchings and partitions

2009 ◽  
Vol DMTCS Proceedings vol. AK,... (Proceedings) ◽  
Author(s):  
Dan Drake ◽  
Jang Soo Kim
Keyword(s):  
Orthogonal Polynomials ◽  
Joint Distribution ◽  
Research Paper ◽  
Set Partitions ◽  
Nous Montrons ◽  
International Audience

International audience We define and consider $k$-distant crossings and nestings for matchings and set partitions, which are a variation of crossings and nestings in which the distance between vertices is important. By modifying an involution of Kasraoui and Zeng (Electronic J. Combinatorics 2006, research paper 33), we show that the joint distribution of $k$-distant crossings and nestings is symmetric. We also study the numbers of $k$-distant noncrossing matchings and partitions for small $k$, which are counted by well-known sequences, as well as the orthogonal polynomials related to $k$-distant noncrossing matchings and partitions. We extend Chen et al.'s $r$-crossings and enhanced $r$-crossings. Nous définissons les notions de croisements et imbrications $k$-distants sur les appariements et les partitions d'ensemble, qui sont une variation sur les notions usuelles prenant en compte la distance entre les sommets. En modifiant une involution de Kasraoui et Zeng (Electronic J. Combinatorics 2006, research paper 33), nous montrons que la distribution jointe des croisements et imbrications $k$-distants est symétrique. Nous étudions le nombre d'involutions et de partitions sans croisement $k$-distant pour de petites valeurs de $k$, qui sont des suites d'entiers bien connues, ainsi que les polynômes orthogonaux qui leur sont reliés. Nous étendons les notions de $r$-croisements et $r$-croisements améliorés dues à Chen et al.

scholarly journals On 1212-Avoiding Restricted Growth Functions

10.37236/6728 ◽  
2017 ◽  
Vol 24 (1) ◽  
Author(s):  
Zhicong Lin ◽  
Shishuo Fu
Keyword(s):  
Recent Work ◽  
Permutation Statistics ◽  
Set Partition ◽  
Noncrossing Partitions ◽  
Growth Functions ◽  
Classical Statistics ◽  
Motzkin Paths

Restricted growth functions (RGFs) avoiding the pattern $1212$ are in natural bijection with noncrossing partitions. Motivated by recent work of Campbell et al., we study five classical statistics bk, ls, lb, rs and rb on $1212$-avoiding RGFs. We show the equidistribution of (ls, rb, lb, bk) and (rb, ls, lb, bk) on $1212$-avoiding RGFs by constructing a simple involution. To our surprise, this result was already proved by Simion 22 years ago via an involution on noncrossing partitions. Our involution, though turns out essentially the same as Simion's, is defined quite differently and has the advantage that makes the discussion more transparent. Consequently, a multiset-valued extension of Simion's result is discovered. Furthermore, similar approach enables us to prove the equidistribution of (mak, rb, rs, bk) and (rb, mak, rs, bk) on $1212$-avoiding RGFs, where "mak" is a set partition statistic introduced by Steingrímsson.Through two bijections to Motzkin paths, we also prove that the triple of classical permutation statistics (exc+1, den, inv — exc) on $321$-avoiding permutations is equidistributed with the triple (bk, rb, rs) on $1212$-avoiding RGFs, which generalizes another result of Simion. In the course, an interesting $q$-analog of the $\gamma$-positivity of Narayana polynomials is found.

scholarly journals Chains of Length 2 in Fillings of Layer Polyominoes

10.37236/3291 ◽  
2013 ◽  
Vol 20 (3) ◽  
Author(s):  
Mitch Phillipson ◽  
Catherine H. Yan ◽  
Jean Yeh
Keyword(s):  
Joint Distribution ◽  
Combinatorial Structures ◽  
Set Partitions ◽  
General Family ◽  
Arbitrary Permutation

The symmetry of the joint distribution of the numbers of crossings and nestings of length $2$ has been observed in many  combinatorial structures, including permutations, matchings, set partitions, linked partitions, and certain families of graphs.  These results have been unified in the larger context of enumeration of northeast and southeast chains of length $2$ in $01$-fillings of moon polyominoes. In this paper  we extend this symmetry to fillings of a more general family—layer polyominoes, which are intersection-free and row-convex, but not necessarily column-convex.  Our main result is that the joint distribution of the numbers of northeast  and southeast chains of length $2$ over $01$-fillings is symmetric and invariant under an arbitrary permutation of rows.

scholarly journals The Generating Function for Total Displacement

10.37236/4329 ◽  
2014 ◽  
Vol 21 (3) ◽  
Author(s):  
Mathieu Guay-Paquet ◽  
Kyle Petersen
Keyword(s):  
Recent Work ◽  
Generating Function ◽  
Simple Form ◽  
Continued Fraction ◽  
Coxeter Groups ◽  
Total Displacement ◽  
Motzkin Paths ◽  
Standard Techniques

In a 1977 paper, Diaconis and Graham studied what Knuth calls the total displacement of a permutation $w$, which is the sum of the distances $|w(i)-i|$. In recent work of the first author and Tenner, this statistic appears as twice the type $A_{n-1}$ version of a statistic for Coxeter groups called the  depth of $w$. There are various enumerative results for this statistic in the work of Diaconis and Graham, codified as exercises in Knuth's textbook, and some other results in the work of Petersen and Tenner. However, no formula for the generating function of this statistic appears in the literature. Knuth comments that "the generating function for total displacement does not appear to have a simple form." In this paper, we translate the problem of computing the distribution of total displacement into a problem of counting weighted Motzkin paths. In this way, standard techniques allow us to express the generating function for total displacement as a continued fraction.

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