I am looking for the asymptotics of the following integral
intmathbbRH2m(x)rme−2alpha2x2rmdx=2m−1/2alpha−2m−1(1−2alpha2)mGamma(m+1/2) 2F1left(−m,m,1/2−m,fracalpha22alpha2−1right)intmathbbRH2m(x)rme−2alpha2x2rmdx=2m−1/2alpha−2m−1(1−2alpha2)mGamma(m+1/2) 2F1left(−m,m,1/2−m,fracalpha22alpha2−1right)
where HmHm is the mrmthmrmth Hermite polynomial (orthogonal under the weight rme−x2rme−x2), and 2F12F1 is the hypergeometric function.
I found this formula from p. 803 of "Table of Integrals, Series, and Products" by Gradshteyn-Ryzhik. However, I have idea about the asymptotics of the 2F12F1 term. Can anyone enlighten me on the asymptotics of
2F1left(−m,m,1/2−m,betaright)2F1left(−m,m,1/2−m,betaright)
when mm is large? In fact I tried mathematica and it seems 2F1left(−m,m,1/2−m,betaright)sim|4beta|m2F1left(−m,m,1/2−m,betaright)sim|4beta|m. Any reference on this issue?
Now given the above asymptotics is true, observe that the norm of HmHm under the weight rme−2alpha2x2rme−2alpha2x2 has the same exponent for all alphaalpha, including the original weight (alpha2=1/2alpha2=1/2). Is this a common phenomenon for orthogonal polynomials?
No comments:
Post a Comment