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...
Saved in:
Published in | Journal of computational and applied mathematics Vol. 232; no. 2; pp. 216 - 226 |
---|---|
Main Author | |
Format | Journal Article |
Language | English |
Published |
Kidlington
Elsevier B.V
15.10.2009
Elsevier |
Subjects | |
Online Access | Get full text |
Cover
Loading…
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 |