Session 18. Harmonic analysis, orthogonal expansions and Dunkl theory

Generalized Brownian processes, random matrices, \(\alpha\) determinant and positive definite functions on Coxeter (permutation) groups

Marek Bożejko, Institute of Mathematics, University of Wrocław, Poland
In my talk we will consider the following subjects:
  1. Positive definite functions on Coxeter groups (W,S) connected with (a) the length function \(|x| = \min\{k: x = s_{1} ... s_{k} , s_{j} \in S\), and representation is minimal\(\}\) and we show that the function \(P(x,q) = q^{|x|}\) is positive definite on W for q in interval \([-1,1]\), (b) also for the "block" lenght function \(||x||\) = the number of different generators in the representation of x as above, we prove that the function \(Q(x,t) = t^{||x||}\) is positive definite on \(W\) for \(t\) in interval \([0,1]\).
  2. Applications: (a) The construction of \(q-CCR\) relations \(A(f) A^*(g) - q A^*(g) A(f) = < f,g>\) for \(f,g\) in a Hilbert space, for real \(q\) and complex \(|q|=1\), and connections with theta function of Jacobi, (b) Free infinitely divisibility of classical normal law \(N(0,1)\), the distributions like \(1/\cosh\) and others classical Meixner laws.
  3. Markov random matrices and special positive definite functions on infinite permutation group related to the number of "isolated" fixed points of a permutation.
  4. Applications to positivity results for \(q\)-determinants and \(\alpha\)-determinants.

References
  1. S.Belinschi, M.Bożejko, F.Lehner, R.Speicher, The normal distribution is free infinitely divisible, Adv.Math. 226(2011), 3677-3698.
  2. M.Bożejko, R.Speicher, Interpolations between bosonic and fermionic relations given by generalized Brownian motion, Math.Z. 222(1996), 135-160.
  3. M.Bożejko, M.Guta, Functors of white noise associated to characters of the infinite symmetric groups, Comm.Math.Phys. 229 (2002),209-227.
  4. M.Bożejko, T.Hasebe, On free infinitely divisibility for classical Meixner distributions, Prob.Math.Stat. 33(2013), 363-375.
  5. M.Bożejko, T.Hirai, Gelfand-Raikov representations of Coxeter groups associated to positive definite norm functions, Prob. Math.Stat. 34(2014).
  6. M.Bożejko, W.Bożejko, Generalized Gaussian processes and positivity of q-determinants and \(\alpha\)-determinants, Preprint, Wrocław 2014,12 pp.
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