Macdonald polynomials and extended Gelfand-Tsetlin graph

The q-Gelfand-Tsetlin graph, Gibbs measures and q-Toeplitz matrices

The problem of the description of finite factor representations of the infinite-dimensional unitary group, investigated by Voiculescu in 1976, is equivalent to the description of all totally positive Toeplitz matrices. Vershik-Kerov showed that this problem is also equivalent to the description of the simplex of central (i.e. possessing a certain Gibbs property) measures on paths in the Gelfand-Tsetlin graph. We study a quantum version of the latter problem. We introduce a notion of a q-centrality and describe the simplex of all q-central measures on paths in the Gelfand-Tsetlin graph. Conject…

Extended Gelfand-Tsetlin graph, its q-boundary, and q-B-splines

A continuation of the joint work by Vadim Gorin and the author, J. Funct. Anal. 270 (2016), 375-418; arXiv:1504.06832. The extended Gelfand-Tsetlin graph, introduced in that paper, is a novel combinatorial object. Its q-boundary is formed by infinite point configurations on a two-sided q-lattice. The q-boundary carries a continuous family of probability measures that are a q-analogue of the so-called zw-measures, which originated in the problem of harmonic analysis on the infinite-dimensional unitary group. In the present paper, it is proved that certain transition Markov kernels, linked to th…

Some Examples of Dynamics for Gelfand Tsetlin Patterns

We give examples of stochastic processes in the Gelfand Tsetlin cone in which each component evolves independently apart from a blocking and pushing interaction. The processes give couplings to certain conditioned Markov processes, last passage times and asymetric exclusion processes. An example of a cone valued process whose components cannot escape past a wall at the origin is also considered.

Non-colliding Jacobi processes as limits of Markov chains on Gelfand-Tsetlin graph

We introduce a stochastic dynamics related to the measures that arise in harmonic analysis on the infinite-dimensional unitary group. Our dynamics is obtained as a limit of a sequence of natural Markov chains on Gelfand-Tsetlin graph. We compute finite-dimensional distributions of the limit Markov process, the generator and eigenfunctions of the semigroup related to this process. The limit process can be identified with Doob h-transform of a family of independent diffusions. Space-time correlation functions of the limit process have a determinantal form.

Universality properties of Gelfand-Tsetlin patterns

A standard Gelfand-Tsetlin pattern of depth $n$ is a configuration of particles in $\{1,...,n\} \times \R$. For each $r \in \{1,...,n\}$, $\{r\} \times \R$ is referred to as the $r^\text{th}$ level of the pattern. A standard Gelfand-Tsetlin pattern has exactly $r$ particles on each level $r$, and particles on adjacent levels satisfy an interlacing constraint. Probability distributions on the set of Gelfand-Tsetlin patterns of depth $n$ arise naturally as distributions of eigenvalue minor processes of random Hermitian matrices of size $n$. We consider such probability spaces when the distributi…

Positive temperature dynamics on Gelfand-Tsetlin patterns restricted by wall

The thesis focuses on processes on symplectic Gelfand-Tsetlin patterns. In chapter 4, a process with dynamics inspired by the Berele correspondence [Ber86] is presented. It is proved that the shape of the pattern is a Doob $h$-transform of independent random walks with $h$ given by the symplectic Schur function. This is followed by an extension to a $q$-weighted version. This randomised version has itself a branching structure and is related to a $q$-deformation of the $so_{2n+1}$-Whittaker functions. In chapter 5, we present a fully randomised process. This process $q$-deforms a process propo…

Gelfand-Tsetlin多胞体与远离极限形状的随机压缩

Gelfand-Tsetlin polytopes and random contractions away from the limiting shapes

研究全旗流形随机压缩下自伴矩阵极值特征值行为，等价于 Gelfand-Tsetlin 多胞体一致测度研究，获显式一致估计与离群行为指数小概率结论。

盖尔芳德 - 采特林模式的宏观形状与自由概率

The macroscopic shape of Gelfand-Tsetlin patterns and free probability

研究盖尔芳德 - 采特林模式与自由概率，定义压缩熵\(\mathcal{H}[F]\)，证明相关等式，通过识别方程表明自由压缩达最大值，将模式视为界面模型计算表面张力，还证明特定模式满足大偏差原理，解决了相关猜想。

Hall-Littlewood polynomials, boundaries, and $p$-adic random matrices

We prove that the boundary of the Hall-Littlewood $t$-deformation of the Gelfand-Tsetlin graph is parametrized by infinite integer signatures, extending results of Gorin and Cuenca on boundaries of related deformed Gelfand-Tsetlin graphs. In the special case when $1/t$ is a prime $p$ we use this to recover results of Bufetov-Qiu and Assiotis on infinite $p$-adic random matrices, placing them in the general context of branching graphs derived from symmetric functions. Our methods rely on explicit formulas for certain skew Hall-Littlewood polynomials. As a separate corollary to these, we obtain …

Harmonic analysis on a finite homogeneous space

In this paper, we study harmonic analysis on finite homogeneous spaces whose associated permutation representation decomposes with multiplicity. After a careful look at Frobenius reciprocity and transitivity of induction, and the introduction of three types of spherical functions, we develop a theory of Gelfand Tsetlin bases for permutation representations. Then we study several concrete examples on the symmetric groups, generalizing the Gelfand pair of the Johnson scheme; we also consider statistical and probabilistic applications. After that, we consider the composition of two permutation re…