Zobrazeno 1 - 10
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pro vyhledávání: '"Costin, R. d."'
We construct a new type of convergent, and asymptotic, representations, dyadic expansions. Their convergence is geometric and the region of convergence often extends from infinity down to $0^+$. We show that dyadic expansions are numerically efficien
Externí odkaz:
http://arxiv.org/abs/2210.17502
Spherical harmonic expansions (SHEs) play an important role in most of the physical sciences, especially in physical geodesy. Despite many decades of investigation, the large order behavior of the SHE coefficients, and the precise domain of convergen
Externí odkaz:
http://arxiv.org/abs/2011.05709
Akademický článek
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Autor:
Costin, O., Costin, R. D.
We construct a new type of convergent asymptotic representations, dyadic factorial expansions. Their convergence is geometric and the region of convergence can include Stokes rays, and often extends down to 0^+. For special functions such as Bessel,
Externí odkaz:
http://arxiv.org/abs/1608.01010
We analyze the one parameter family of tronqu\'ee solutions of the Painlev\'e equation \P1 in the pole-free sectors together with the region of the first array of poles. We find a convergent expansion for these solutions, containing one free paramete
Externí odkaz:
http://arxiv.org/abs/1310.5330
Autor:
Costin, O., Costin, R. D.
Publikováno v:
SIAM.J.Math.Anal. v27 no1 (1996)
We study the $\epsilon \to 0$ behavior of recurrence relations of the type $\sum_{j=0}^l a_j(k\epsilon,\epsilon)y_{k+j}=0,$ $k\in \zdd$ ($l$ fixed). The $a_j$ are $C^{\infty}$ functions in each variable on $I\times [0,\e_0]$ for a bounded interval $I
Externí odkaz:
http://arxiv.org/abs/math/0608413
We analyze the time evolution of a one-dimensional quantum system with an attractive delta function potential whose strength is subjected to a time periodic (zero mean) parametric variation. We show that for generic forcing which includes the sum of
Externí odkaz:
http://arxiv.org/abs/math-ph/0608038
Publikováno v:
Proc. R. Soc. Lond. A 460, 363--3641 (2004)
A rigorous way to obtain sharp bounds for Stokes constants is introduced and illustrated on a concrete problem arising in applications.
Externí odkaz:
http://arxiv.org/abs/math/0608316
Publikováno v:
J. Stat. Phys.1--4 283-310 (2004)
We study the transition to the continuum of an initially bound quantum particle in $\RR^d$, $d=1,2,3$, subjected, for $t\ge 0$, to a time periodic forcing of arbitrary magnitude. The analysis is carried out for compactly supported potentials, satisfy
Externí odkaz:
http://arxiv.org/abs/math-ph/0608030
Autor:
Costin, O, Costin, R D
For the hypoelliptic differential operators $P={\partial^2_ x}+(x^k\partial_ y -x^l{\partial_t})^2$ introduced by T. Hoshiro, generalizing a class of M. Christ, in the cases of $k$ and $l$ left open in the analysis, the operators $P$ also fail to be
Externí odkaz:
http://arxiv.org/abs/math/0212167