Random Young Diagrams Research Articles

Asymptotics of Some Plancherel Averages Via Polynomiality Results

Consider Young diagrams of n boxes distributed according to the Plancherel measure. So those diagrams could be the output of the RSK algorithm, when applied to random permutations of the set {1,ldots ,n}. Here we are interested in asymptotics, as nrightarrow infty , of expectations of certain functions of random Young diagrams, such as the number of bumping steps of the RSK algorithm that leads to that diagram, the side length of its Durfee square, or the logarithm of its probability. We can express these functions in terms of hook lengths or contents of the boxes of the diagram, which opens the door for application of known polynomiality results for Plancherel averages. We thus obtain representations of expectations as binomial convolutions, that can be further analyzed with the help of Rice’s integral or Poisson generating functions. Among our results is a very explicit expression for the constant appearing in the almost equipartition property of the Plancherel measure.

The Limiting Distribution of the Hook Length of a Randomly Chosen Cell in a Random Young Diagram

Let $p(n)$ be the number of all integer partitions of the positive integer $n$ and let $\lambda$ be a partition, selected uniformly at random from among all such $p(n)$ partitions. It is known that each partition $\lambda$ has a unique graphical representation, composed by $n$ non-overlapping cells in the plane called Young diagram. As a second step of our sampling experiment, we select a cell $c$ uniformly at random from among all $n$ cells of the Young diagram of the partition $\lambda$. For large $n$, we study the asymptotic behavior of the hook length $Z_n=Z_n(\lambda,c)$ of the cell $c$ of a random partituion $\lambda$. This two-step sampling procedure suggests a product probability measure, which assigns the probability $1/np(n)$ to each pair $(\lambda,c)$. With respect to this probability measure, we show that the random variable $\pi Z_n/\sqrt{6n}$ converges weakly, as $n\to\infty$, to a random variable whose probability density function equals $6y/\pi^2 (e^y-1)$ if $0<y<\infty$, and zero elsewhere.

The Limiting Distribution of the Hook Length of a Randomly Chosen Cell in a Random Young Diagram

Пусть $p(n)$ - количество всех целочисленных разбиений положительного целого числа $n$, и пусть $\lambda $ - разбиение, выбранное случайно и равновероятно из всех таких $p(n)$ разбиений. Известно, что каждое разбиение $\lambda $ имеет единственное графическое представление, состоящее из $n$ неперекрывающихся ячеек на плоскости, называемое диаграммой Юнга. В качестве второго шага нашего выборочного эксперимента мы выбираем из $n$ ячеек диаграммы Юнга разбиения $\lambda $ случайно и равновероятно ячейку $c$. Для больших значений $n$ мы изучаем асимптотическое поведение длины крюка $Z_n=Z_n(\lambda ,c)$ ячейки $c$ случайного разбиения $\lambda $. Эта двухэтапная выборочная процедура порождает вероятностную меру, которая приписывает вероятность $1/np(n)$ каждой паре $(\lambda ,c)$. Показано, что относительно этой вероятностной меры случайная величина $\pi Z_n/\sqrt {6n}$ слабо сходится при $n\to \infty $ к случайной величине, плотность функции распределения которой равна $6y/(\pi ^2(e^y-1))$, если $0&lt;y&lt;\infty $, и нулю в остальных случаях. Доказательство основано на подходе Хеймана к исследованию седловой точки для допустимых степенных рядов.

Asymptotics of Jack characters

Jack characters are a one-parameter deformation of the characters of the symmetric groups; a deformation given by the coefficients in the expansion of Jack symmetric functions in the basis of power-sum symmetric functions. We study Jack characters from the viewpoint of the asymptotic representation theory. In particular, we give explicit formulas for their asymptotically top-degree part, in terms of bicolored oriented maps with an arbitrary face structure. We also study their multiplicative structure and their structure constants and we prove that they fulfill approximate factorization property, a convenient tool for proving Gaussianity of fluctuations of random Young diagrams.

Randomized box–ball systems, limit shape of rigged configurations and thermodynamic Bethe ansatz

We introduce a probability distribution on the set of states in a generalized box–ball system associated with Kirillov–Reshetikhin (KR) crystals of type An(1). Their conserved quantities induce n-tuple of random Young diagrams in the rigged configurations. We determine their limit shape as the system gets large by analyzing the Fermionic formula by thermodynamic Bethe ansatz. The result is expressed as a logarithmic derivative of a deformed character of the KR modules and agrees with the stationary local energy of the associated Markov process of carriers.

Gaussian fluctuations of Jack-deformed random Young diagrams

We introduce a large class of random Young diagrams which can be regarded as a natural one-parameter deformation of some classical Young diagram ensembles; a deformation which is related to Jack polynomials and Jack characters. We show that each such a random Young diagram converges asymptotically to some limit shape and that the fluctuations around the limit are asymptotically Gaussian.

Asymptotic joint distribution of the extremities of a random Young diagram and enumeration of graphical partitions

An integer partition of n is a decreasing sequence of positive integers that add up to [n]. Back in 1979 Macdonald posed a question about the limit value of the probability that two partitions chosen uniformly at random, and independently of each other, are comparable in terms of the dominance order. In 1982 Wilf conjectured that the uniformly random partition is a size-ordered degree sequence of a simple graph with the limit probability 0. In 1997 we showed that in both, seemingly unrelated, cases the limit probabilities are indeed zero, but our method left open the problem of convergence rates. The main result in this paper is that each of the probabilities is e−0.11log⁡n/log⁡log⁡n, at most. A key element of the argument is a local limit theorem, with convergence rate, for the joint distribution of the [n1/4−ε] tallest columns and the [n1/4−ε] longest rows of the Young diagram representing the random partition.

Gaussian fluctuations of Young diagrams and structure constants of Jack characters

In this paper, we consider a deformation of Plancherel measure linked to Jack polynomials. Our main result is the description of the first- and second-order asymptotics of the bulk of a random Young diagram under this distribution, which extends celebrated results of Vershik, Kerov, Logan, and Shepp (for the first-order asymptotics) and Kerov (for the second-order asymptotics). This gives more evidence for the connection with the Gaussian β-ensemble, already suggested by a work of Matsumoto. Our main tool is a polynomiality result for the structure constants of some quantities that we call Jack characters, recently introduced by Lassalle. We believe that this result is also interesting in itself and we give several other applications of it.

A Diffusive Limit for the Profiles of Random Young Diagrams by Way of Free Probability

Concentration phenomena in statistical ensembles of Young diagrams have been investigated as static models first for the Plancherel ensemble by Vershik–Kerov and Logan–Shepp in 1970s and later in some other group-theoretical setting by Biane. On the other hand, a dynamical model of concentration for Young diagrams, which is not directly connected with group representations, was shown by Funak–{Sasada in the framework of hydrodynamic limit. The aim of this paper is to present a new dynamical model of concentration for Young diagrams featuring the group-theoretical sense. Starting from an initial state yielding concentration and a microscopic dynamics keeping the Plancherel measure invariant, we derive an evolution of the profiles of Young diagrams under a diffusive scaling limit. The resulting evolution along macroscopic time is described in terms of the notions of Voiculescu's free probability theory such as free compression and free convolution of Kerov transition measures.

Law of Large Numbers for infinite random matrices over a finite field

Asymptotic representation theory of general linear groups $$\hbox {GL}(n,F_\mathfrak {q})$$ over a finite field leads to studying probability measures $$\rho $$ on the group $$\mathbb {U}$$ of all infinite uni-uppertriangular matrices over $$F_\mathfrak {q}$$ , with the condition that $$\rho $$ is invariant under conjugations by arbitrary infinite matrices. Such probability measures form an infinite-dimensional simplex, and the description of its extreme points (in other words, ergodic measures $$\rho $$ ) was conjectured by Kerov in connection with nonnegative specializations of Hall–Littlewood symmetric functions. Vershik and Kerov also conjectured the following Law of Large Numbers. Consider an infinite random matrix drawn from an ergodic measure coming from the Kerov’s conjectural classification and its $$n \times n$$ submatrix formed by the first rows and columns. The sizes of Jordan blocks of the submatrix can be interpreted as a (random) partition of $$n$$ , or, equivalently, as a (random) Young diagram $$\lambda (n)$$ with $$n$$ boxes. Then, as $$n\rightarrow \infty $$ , the rows and columns of $$\lambda (n)$$ have almost sure limiting frequencies corresponding to parameters of this ergodic measure. Our main result is the proof of this Law of Large Numbers. We achieve it by analyzing a new randomized Robinson–Schensted–Knuth (RSK) insertion algorithm which samples random Young diagrams $$\lambda (n)$$ coming from ergodic measures. The probability weights of these Young diagrams are expressed in terms of Hall–Littlewood symmetric functions. Our insertion algorithm is a modified and extended version of a recent construction by Borodin and Petrov (2013). On the other hand, our randomized RSK insertion generalizes a version of the RSK insertion introduced by Vershik and Kerov (SIAM J. Algebr. Discret. Math. 7(1):116–124, 1986) in connection with asymptotic representation theory of symmetric groups (which is governed by nonnegative specializations of Schur symmetric functions).

Equivalence of Ensembles Under Inhomogeneous Conditioning and Its Applications to Random Young Diagrams

We prove the equivalence of ensembles or a realization of the local equilibrium for Bernoulli measures on \({\mathbb{Z}}\) conditioned on two conserved quantities under the situation that one of them is spatially inhomogeneous. For the proof, we extend the classical local limit theorem for a sum of Bernoulli independent sequences to those multiplied by linearly growing weights. The motivation comes from the study of random Young diagrams and their evolutional models, which were originally suggested by Herbert Spohn. We discuss the relation between our result and the so-called Vershik curve which appears in a scaling limit for height functions of two-dimensional Young diagrams. We also discuss a related random dynamics.

On Kerov polynomials for Jack characters (extended abstract)

We consider a deformation of Kerov character polynomials, linked to Jack symmetric functions. It has been introduced recently by M. Lassalle, who formulated several conjectures on these objects, suggesting some underlying combinatorics. We give a partial result in this direction, showing that some quantities are polynomials in the Jack parameter $\alpha$ with prescribed degree. Our result has several interesting consequences in various directions. Firstly, we give a new proof of the fact that the coefficients of Jack polynomials expanded in the monomial or power-sum basis depend polynomially in $\alpha$. Secondly, we describe asymptotically the shape of random Young diagrams under some deformation of Plancherel measure.

Block characters of the symmetric groups

A block character of a finite symmetric group is a positive definite function which depends only on the number of cycles in a permutation. We describe the cone of block characters by identifying its extreme rays, and find relations of the characters to descent representations and the coinvariant algebra of ${\mathfrak{S}}_{n}$ . The decomposition of extreme block characters into the sum of characters of irreducible representations gives rise to certain limit shape theorems for random Young diagrams. We also study counterparts of the block characters for the infinite symmetric group ${\mathfrak{S}}_{\infty}$ , along with their connection to the Thoma characters of the infinite linear group GL ?(q) over a Galois field.

A central limit theorem for extremal characters of the infinite symmetric group

The asymptotic behavior of the lengths of the first rows and columns in the random Young diagrams corresponding to extremal characters of the infinite symmetric group is studied. We consider rows and columns with linear growth in n and prove a central limit theorem for their lengths in the case of distinct Thoma parameters. We also prove a more precise statement relating the growth of rows and columns of Young diagrams to a simple independent random sampling model.

Random Young Diagrams in a Rectangular Box

We exhibit the limit shape of random Young diagrams having a distribution proportional to the exponential of their area, and confined in a rectangular box. The Ornstein-Uhlenbeck bridge arises from the fluctuations around the limit shape.

Asymptotics of q-plancherel measures

In this paper, we are interested in the asymptotic size of the rows and columns of a random Young diagram under a natural deformation of the Plancherel measure coming from Hecke algebras. The first lines of such diagrams are typically of order n, so it does not fit in the context of the work of Biane (Int Math Res Notices 4:179–192, 2001) and Śniady (Probab. Theory Relat Fields 136:263–297, 2006). Using the theory of polynomial functions on Young diagrams of Kerov and Olshanski, we are able to compute explicitly the first- and second-order asymptotics of the length of the first rows. Our method also works for other measures, for example those coming from Schur–Weyl representations.

Transition distributions of young diagrams under periodically weighted plancherel measures

Kerov[16,17] proved that Wigner’s semi-circular law in Gaussian unitary ensembles is the transition distribution of the omega curve discovered by Vershik and Kerov[34] for the limit shape of random partitions under the Plancherel measure. This establishes a close link between random Plancherel partitions and Gaussian unitary ensembles. In this paper we aim to consider a general problem, namely, to characterize the transition distribution of the limit shape of random Young diagrams under Poissonized Plancherel measures in a periodic potential, which naturally arises in Nekrasov’s partition functions and is further studied by Nekrasov and Okounkov[25] and Okounkov[28,29]. We also find an associated matrix model for this transition distribution. Our argument is based on a purely geometric analysis on the relation between matrix models and Seiberg-Witten differentials.

Asymptotics for random Young diagrams when the word length and alphabet size simultaneously grow to infinity

Given a random word of size $n$ whose letters are drawn independently from an ordered alphabet of size $m$, the fluctuations of the shape of the random RSK Young tableaux are investigated, when $n$ and $m$ converge together to infinity. If $m$ does not grow too fast and if the draws are uniform, then the limiting shape is the same as the limiting spectrum of the GUE. In the non-uniform case, a control of both highest probabilities will ensure the convergence of the first row of the tableau toward the Tracy--Widom distribution.

Markov processes on partitions

We introduce and study a family of Markov processes on partitions. The processes preserve the so-called z-measures on partitions previously studied in connection with harmonic analysis on the infinite symmetric group. We show that the dynamical correlation functions of these processes have determinantal structure and we explicitly compute their correlation kernels. We also compute the scaling limits of the kernels in two different regimes. The limit kernels describe the asymptotic behavior of large rows and columns of the corresponding random Young diagrams, and the behavior of the Young diagrams near the diagonal.Our results show that recently discovered analogy between random partitions arising in representation theory and spectra of random matrices extends to the associated time– dependent models.

Random Young Diagram, Variational Method, and Related Problems

Using the local method, we prove the large deviation principle for one model distribution, derive an explicit expression for the rate function, and outline ways to further apply the method presented.