Distributions of truncations of the heat kernel on the complex projective space

Nizar Demni[1]

  • [1] Institut de Recherche en Mathématiques de Rennes Université de Rennes 1 Campus de Beaulieu 35042 Rennes FRANCE

Annales mathématiques Blaise Pascal (2014)

  • Volume: 21, Issue: 2, page 1-20
  • ISSN: 1259-1734

Abstract

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Let ( U t ) t 0 be a Brownian motion valued in the complex projective space P N - 1 . Using unitary spherical harmonics of homogeneous degree zero, we derive the densities of | U t 1 | 2 and of ( | U t 1 | 2 , | U t 2 | 2 ) , and express them through Jacobi polynomials in the simplices of and 2 respectively. More generally, the distribution of ( | U t 1 | 2 , , | U t k | 2 ) , 2 k N - 1 may be derived using the decomposition of the unitary spherical harmonics under the action of the unitary group 𝒰 ( N - k + 1 ) yet computations become tedious. We also revisit the approach initiated in [13] and based on a partial differential equation (hereafter pde) satisfied by the Laplace transform of the density. When k = 1 , we invert the Laplace transform and retrieve the expression already derived using spherical harmonics. For general 1 k N - 2 , integrations by parts performed on the pde lead to a heat equation in the simplex of k .

How to cite

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Demni, Nizar. "Distributions of truncations of the heat kernel on the complex projective space." Annales mathématiques Blaise Pascal 21.2 (2014): 1-20. <http://eudml.org/doc/275449>.

@article{Demni2014,
abstract = {Let $(U_t)_\{t \ge 0\}$ be a Brownian motion valued in the complex projective space $\mathbb\{C\}P^\{N-1\}$. Using unitary spherical harmonics of homogeneous degree zero, we derive the densities of $|U_t^\{1\}|^2$ and of $(|U_t^\{1\}|^2, |U_t^2|^2)$, and express them through Jacobi polynomials in the simplices of $\mathbb\{R\}$ and $\mathbb\{R\}^2$ respectively. More generally, the distribution of $(|U_t^\{1\}|^2, \dots , |U_t^k|^2), \;2 \le k \le N-1$ may be derived using the decomposition of the unitary spherical harmonics under the action of the unitary group $\mathcal\{U\}(N-k+1)$ yet computations become tedious. We also revisit the approach initiated in [13] and based on a partial differential equation (hereafter pde) satisfied by the Laplace transform of the density. When $k=1$, we invert the Laplace transform and retrieve the expression already derived using spherical harmonics. For general $1 \le k \le N-2$, integrations by parts performed on the pde lead to a heat equation in the simplex of $\mathbb\{R\}^k$.},
affiliation = {Institut de Recherche en Mathématiques de Rennes Université de Rennes 1 Campus de Beaulieu 35042 Rennes FRANCE},
author = {Demni, Nizar},
journal = {Annales mathématiques Blaise Pascal},
keywords = {Brownian motion; complex projective space; Dirichlet distribution; Jacobi polynomials in the simplex; unitary spherical harmonics; Jacobi polynomials; simplices; Laplace transform; heat equation},
language = {eng},
month = {7},
number = {2},
pages = {1-20},
publisher = {Annales mathématiques Blaise Pascal},
title = {Distributions of truncations of the heat kernel on the complex projective space},
url = {http://eudml.org/doc/275449},
volume = {21},
year = {2014},
}

TY - JOUR
AU - Demni, Nizar
TI - Distributions of truncations of the heat kernel on the complex projective space
JO - Annales mathématiques Blaise Pascal
DA - 2014/7//
PB - Annales mathématiques Blaise Pascal
VL - 21
IS - 2
SP - 1
EP - 20
AB - Let $(U_t)_{t \ge 0}$ be a Brownian motion valued in the complex projective space $\mathbb{C}P^{N-1}$. Using unitary spherical harmonics of homogeneous degree zero, we derive the densities of $|U_t^{1}|^2$ and of $(|U_t^{1}|^2, |U_t^2|^2)$, and express them through Jacobi polynomials in the simplices of $\mathbb{R}$ and $\mathbb{R}^2$ respectively. More generally, the distribution of $(|U_t^{1}|^2, \dots , |U_t^k|^2), \;2 \le k \le N-1$ may be derived using the decomposition of the unitary spherical harmonics under the action of the unitary group $\mathcal{U}(N-k+1)$ yet computations become tedious. We also revisit the approach initiated in [13] and based on a partial differential equation (hereafter pde) satisfied by the Laplace transform of the density. When $k=1$, we invert the Laplace transform and retrieve the expression already derived using spherical harmonics. For general $1 \le k \le N-2$, integrations by parts performed on the pde lead to a heat equation in the simplex of $\mathbb{R}^k$.
LA - eng
KW - Brownian motion; complex projective space; Dirichlet distribution; Jacobi polynomials in the simplex; unitary spherical harmonics; Jacobi polynomials; simplices; Laplace transform; heat equation
UR - http://eudml.org/doc/275449
ER -

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