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Difference between revisions of "Hermite transform"

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$$  
 
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F ( x)  =  \sum _ { n= } 0 ^  \infty   
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\frac{f ( n) }{2  ^ {n} n ! }
 
\frac{f ( n) }{2  ^ {n} n ! }
 
  H _ {n} ( x)  = \  
 
  H _ {n} ( x)  = \  
H  ^ {-} 1 \{ f ( n) \} ,\  - \infty < x < \infty ,
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H  ^ {-1} \{ f ( n) \} ,\  - \infty < x < \infty ,
 
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Latest revision as of 21:42, 27 December 2020


The integral

$$ f ( n) = H \{ F ( x) \} = \int\limits _ {- \infty } ^ \infty e ^ {- x ^ {2} } H _ {n} ( x) F ( x) d x ,\ \ n = 0 , 1 \dots $$

where $ H _ {n} ( x) $ are the Hermite polynomials. The inversion formula is

$$ F ( x) = \sum _ { n= 0} ^ \infty \frac{1}{\sqrt \pi } \frac{f ( n) }{2 ^ {n} n ! } H _ {n} ( x) = \ H ^ {-1} \{ f ( n) \} ,\ - \infty < x < \infty , $$

provided that the series converges. The Hermite transform reduces the operator

$$ R [ F ( x) ] = e ^ {x ^ {2} } \frac{d}{dx} \left [ e ^ {x ^ {2} } \frac{d}{dx} F ( x) \right ] $$

to an algebraic one by the formula

$$ H \{ R [ F ( x) ] \} = - 2 n f ( n) . $$

If $ F $ and all its derivatives up to and including the $ p $- th order are bounded, then

$$ H \{ F ^ { ( p) } ( x) \} = f ( n + p ) . $$

The Hermite transform has also been introduced for a special class of generalized functions (see [2]). They are used to solve differential equations containing the operator $ R $.

References

[1] L. Debnath, "On the Hermite transform" Mat. Vesnik , 1 (1964) pp. 285–292
[2] A.G. Zemanian, "Generalized integral transforms" , Wiley (1968)
How to Cite This Entry:
Hermite transform. Encyclopedia of Mathematics. URL: http://encyclopediaofmath.org/index.php?title=Hermite_transform&oldid=47217
This article was adapted from an original article by Yu.A. BrychkovA.P. Prudnikov (originator), which appeared in Encyclopedia of Mathematics - ISBN 1402006098. See original article