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Reference.org
Hahn polynomials
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Orthogonality
∑ x = 0 N − 1 Q n ( x ) Q m ( x ) ρ ( x ) = 1 π n δ m , n , {\displaystyle \sum _{x=0}^{N-1}Q_{n}(x)Q_{m}(x)\rho (x)={\frac {1}{\pi _{n}}}\delta _{m,n},} ∑ n = 0 N − 1 Q n ( x ) Q n ( y ) π n = 1 ρ ( x ) δ x , y {\displaystyle \sum _{n=0}^{N-1}Q_{n}(x)Q_{n}(y)\pi _{n}={\frac {1}{\rho (x)}}\delta _{x,y}}
where
δx,y
is the Kronecker delta function and the weight functions are
ρ ( x ) = ρ ( x ; α ; β , N ) = ( α + x x ) ( β + N − 1 − x N − 1 − x ) / ( N + α + β N − 1 ) {\displaystyle \rho (x)=\rho (x;\alpha ;\beta ,N)={\binom {\alpha +x}{x}}{\binom {\beta +N-1-x}{N-1-x}}/{\binom {N+\alpha +\beta }{N-1}}}
and
π n = π n ( α , β , N ) = ( N − 1 n ) 2 n + α + β + 1 α + β + 1 Γ ( β + 1 , n + α + 1 , n + α + β + 1 ) Γ ( α + 1 , α + β + 1 , n + β + 1 , n + 1 ) / ( N + α + β + n n ) {\displaystyle \pi _{n}=\pi _{n}(\alpha ,\beta ,N)={\binom {N-1}{n}}{\frac {2n+\alpha +\beta +1}{\alpha +\beta +1}}{\frac {\Gamma (\beta +1,n+\alpha +1,n+\alpha +\beta +1)}{\Gamma (\alpha +1,\alpha +\beta +1,n+\beta +1,n+1)}}/{\binom {N+\alpha +\beta +n}{n}}} .
Relation to other polynomials
Racah polynomials
are a generalization of Hahn polynomials
Chebyshev, P. (1907), "Sur l'interpolation des valeurs équidistantes", in Markoff, A.; Sonin, N. (eds.),
Oeuvres de P. L. Tchebychef
, vol. 2, pp. 219–242, Reprinted by Chelsea
Hahn, Wolfgang
(1949), "Über Orthogonalpolynome, die q-Differenzengleichungen genügen",
Mathematische Nachrichten
, 2: 4–34,
doi
:
10.1002/mana.19490020103
,
ISSN
0025-584X
,
MR
0030647
Koekoek, Roelof; Lesky, Peter A.; Swarttouw, René F. (2010),
Hypergeometric orthogonal polynomials and their q-analogues
, Springer Monographs in Mathematics, Berlin, New York:
Springer-Verlag
,
doi
:
10.1007/978-3-642-05014-5
,
ISBN
978-3-642-05013-8,
MR
2656096
Koornwinder, Tom H.; Wong, Roderick S. C.; Koekoek, Roelof; Swarttouw, René F. (2010),
"Hahn Class: Definitions"
, in
Olver, Frank W. J.
; Lozier, Daniel M.; Boisvert, Ronald F.; Clark, Charles W. (eds.),
NIST Handbook of Mathematical Functions
, Cambridge University Press,
ISBN
978-0-521-19225-5,
MR
2723248
.