The Liouville-Stekloff method for approximating solutions of homogeneous linear ODE and a general result due to Tricomi which provides estimates for the zeros of functions by means of the knowledge of an asymptotic representation are used in order to improve a classical asymptotic formula for the gr
The asymptotics of the generalised Hermite–Bell polynomials
✍ Scribed by R.B. Paris
- Publisher
- Elsevier Science
- Year
- 2009
- Tongue
- English
- Weight
- 992 KB
- Volume
- 232
- Category
- Article
- ISSN
- 0377-0427
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✦ Synopsis
The Hermite-Bell polynomials are defined by H r n (x) = (-) n exp(x r )(d/dx) n exp(-x r ) for n = 0, 1, 2, . . . and integer r ≥ 2 and generalise the classical Hermite polynomials corresponding to r = 2. We obtain an asymptotic expansion for H r n (x) as n → ∞ using the method of steepest descents. For a certain value of x, two saddle points coalesce and a uniform approximation in terms of Airy functions is given to cover this situation. An asymptotic approximation for the largest positive zeros of H r n (x) is derived as n → ∞.
Numerical results are presented to illustrate the accuracy of the various expansions.
📜 SIMILAR VOLUMES
We analyze the Bell polynomials B n (x) asymptotically as n → ∞. We obtain asymptotic approximations from the differential-difference equation which they satisfy, using a discrete version of the ray method. We give some examples showing the accuracy of our formulas.