中文

多区间上的正交多项式:递推系数与零点的聚点

经典分析与常微分方程 2010-01-05 v1 复变函数

摘要

E=j=1l[a2j1,a2j],E = \cup_{j = 1}^l [a_{2j-1},a_{2j}], a1<a2<...<a2l,a_1 < a_2 < ... < a_{2l}, l2l \geq 2 并设 {\boldmath\omega}(\infty) =(\omega_1(\infty),...,\omega_{l-1}(\infty)),其中 ωj()\omega_j(\infty)[a2j1,a2j][a_{2 j - 1}, a_{2 j}] 在无穷远处的调和测度。设 μ\muEE 上的绝对连续测度,满足 Szeg\H{o} 条件,且在 EE 之外至多有有限个点测度,并记 (Pn)(P_n)(Qn)({\mathcal Q}_n) 为关于 dμd\mu 的正交归一多项式及其相关的 Weyl 解,满足递推关系 λ2+ny1+n=(xα1+n)ynλ1+ny1+n\sqrt{\lambda_{2 + n}} y_{1 + n} = (x - \alpha_{1 + n}) y_n -\sqrt{\lambda_{1 + n}} y_{-1 + n}。我们证明递推系数在拓扑上与序列 (n {\boldmath\omega}(\infty))_{n\in \mathbb N} 模1具有相同的收敛行为;更准确地说,设 ({\boldmath\alpha}^{l-1}_{1 + n}, {\boldmath\lambda}^{l-1}_{2 + n}) = (α[l12]+1+n,...,(\alpha_{[\frac{l 1}{2}]+1+n},..., α1+n,...,\alpha_{1+n},..., α[l22]+1+n,\alpha_{-[\frac{l-2}{2}]+1+n}, λ[l22]+2+n,\lambda_{[\frac{l-2}{2}]+2+n}, ...,λ2+n,...,\lambda_{2+n}, ...,..., λ[l12]+2+n)\lambda_{-[\frac{l-1}{2}]+2+n}),我们证明 ({\boldmath\alpha}^{l-1}_{1 + n_\nu}, {\boldmath\lambda}^{l-1}_{2 + n_\nu})_{\nu \in \mathbb N} 收敛当且仅当 (n_\nu {\boldmath\omega}(\infty))_{\nu \in \mathbb N} 模1收敛,并且我们给出了 ({\boldmath\alpha}^{l-1}_{1 + n}, {\boldmath\lambda}^{l-1}_{2 + n}) 的聚点集与 (n{\boldmath\omega}(\infty)) 模1的聚点集之间的一个显式同胚。

关键词

引用

@article{arxiv.1001.0478,
  title  = {Orthogonal polynomials on several intervals: accumulation points of recurrence coefficients and of zeros},
  author = {Franz Peherstorfer},
  journal= {arXiv preprint arXiv:1001.0478},
  year   = {2010}
}

备注

The last modifications and corrections of this manuscript were done by the author in the two months preceding this passing away in November 2009. The manuscript is not published elsewhere