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Dan Dai

Publications and source records attributed to Dan Dai.

42 records · Page 3Linked to original sources
arXiv2013

Plancherel-Rotach asymptotic expansion for some polynomials from indeterminate moment problems

We study the Plancherel--Rotach asymptotics of four families of orthogonal polynomials, the Chen--Ismail polynomials, the Berg-Letessier-Valent polynomials, the Conrad--Flajolet polynomials I and II. All these polynomials arise in indeterminate moment problems and three of them are birth and death process polynomials with cubic or quartic rates. We employ a difference equation asymptotic technique due to Z. Wang and R. Wong. Our analysis leads to a conjecture about large degree behavior of polynomials orthogonal with respect to solutions of indeterminate moment problems.

math.CA↗
arXiv2013

Existence and Uniqueness of Tronquée Solutions of the Third and Fourth Painlevé Equations

It is well-known that the first and second Painlevé equations admit solutions characterised by divergent asymptotic expansions near infinity in specified sectors of the complex plane. Such solutions are pole-free in these sectors and called tronquée solutions by Boutroux. In this paper, we show that similar solutions exist for the third and fourth Painlevé equations as well.

math.CA↗
arXiv2009

Painlevé VI and Hankel determinants for the generalized Jacobi Weight

We study the Hankel determinant of the generalized Jacobi weight $(x-t)^γx^α(1-x)^β$ for $x\in[0,1]$ with $α, β>0$, $t < 0 $ and $γ\in\mathbb{R}$. Based on the ladder operators for the corresponding monic orthogonal polynomials $P_n(x)$, it is shown that the logarithmic derivative of Hankel determinant is characterized by a $τ$-function for the Painlevé VI system.

math.CA↗
arXiv2008

Painlevé V and a Pollaczek-Jacobi type orthogonal polynomials

We study a sequence of polynomials orthogonal with respect to a one parameter family of weights $$ w(x):=w(x,t)=\rex^{-t/x}\:x^{\al}(1-x)^{\bt},\quad t\geq 0, $$ defined for $x\in[0,1].$ If $t=0,$ this reduces to a shifted Jacobi weight. Our ladder operator formalism and the associated compatibility conditions give an easy determination of the recurrence coefficients. For $t>0,$ the factor $\rex^{-t/x}$ induces an infinitely strong zero at $x=0.$ With the aid of the compatibility conditions, the recurrence coefficients are expressed in terms of a set of auxiliary quantities that satisfy a system of difference equations. These, when suitably combined with a pair of Toda-like equations derived from the orthogonality principle, show that the auxiliary quantities are a particular Painlevé V and/or allied functions. It is also shown that the logarithmic derivative of the Hankel determinant, $$ D_n(t):=\det(\int_{0}^{1} x^{i+j} \:\rex^{-t/x}\:x^{\al}(1-x)^{\bt}dx)_{i,j=0}^{n-1}, $$ satisfies the Jimbo-Miwa-Okamoto $σ-$form of the Painlevé V and that the same quantity satisfies a second order non-linear difference equation which we believe to be new.

math.CA↗
arXiv2008

Painleve IV asymptotics for orthogonal polynomials with respect to a modified Laguerre weight

We study polynomials that are orthogonal with respect to the modified Laguerre weight $z^{-n + ν} e^{-Nz} (z-1)^{2b}$ in the limit where $n, N \to \infty$ with $N/n \to 1$ and $ν$ is a fixed number in $\mathbb{R} \setminus \mathbb{N}_0$. With the effect of the factor $(z-1)^{2b}$, the local parametrix near the critical point $z =1$ can be constructed in terms of $Ψ$-functions associated with the Painleve IV equation. We show that the asymptotics of the recurrence coefficients of orthogonal polynomials can be described in terms of specified solution of the Painleve IV equation in the double scaling limit. Our method is based on the Deift/Zhou steepest decent analysis of the Riemann-Hilbert problem associated with orthogonal polynomials.

math.CA↗