The asymptotics of the generalised Hermite–Bell polynomials

The Hermite–Bell polynomials are defined by H n r ( x ) = ( − ) n exp ( x r ) ( d / d x ) 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 n r ( x ) as n → ∞ using the method of s...

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Bibliographic Details
Published inJournal of computational and applied mathematics Vol. 232; no. 2; pp. 216 - 226
Main Author Paris, R.B.
Format Journal Article
LanguageEnglish
Published Kidlington Elsevier B.V 15.10.2009
Elsevier
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Summary:The Hermite–Bell polynomials are defined by H n r ( x ) = ( − ) n exp ( x r ) ( d / d x ) 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 n r ( 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 n r ( x ) is derived as n → ∞ . Numerical results are presented to illustrate the accuracy of the various expansions.
Bibliography:ObjectType-Article-2
SourceType-Scholarly Journals-1
ObjectType-Feature-1
content type line 23
ISSN:0377-0427
1879-1778
DOI:10.1016/j.cam.2009.05.031