## Let x (*) n, k , k=1, 2, ..., [nΓ2], denote the k th positive zero in increasing order of the ultraspherical polynomial P (\*) n (x). We prove that the function [\*+(2n 2 +1)Γ (4n+2)] 1Γ2 x (\*) n, k increases as \* increases for \*> &1Γ2. The proof is based on two integrals involved with the s
On a Conjecture Concerning Monotonicity of Zeros of Ultraspherical Polynomials
β Scribed by Dimitar K. Dimitrov
- Publisher
- Elsevier Science
- Year
- 1996
- Tongue
- English
- Weight
- 235 KB
- Volume
- 85
- Category
- Article
- ISSN
- 0021-9045
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β¦ Synopsis
Let C * n , n=0, 1, ..., *>&1Γ2 be the ultraspherical (Gegenbauer) polynomials, orthogonal on (&1, 1) with respect to the weight (1&x 2 ) *&1Γ2 . Denote by n, k (\*), k=1, ..., [nΓ2] the positive zeros of C \* n enumerated in decreasing order. The problem of finding the ``extremal'' function f for which the products f (\*) n, k (*) are increasing functions of * is of recent interest. Ismail, Letessier, and Askey conjectured that f (*)=(*+1) 1Γ2 is the function to solve this problem. We prove the conjecture for sufficiently large n and some related results. 1996 Academic Press, Inc. 0 Z$ n, k (*)= f $ n, k (*) n, k (\*)+ f n, k (\*) $ n, k (*), article no. 0030 88
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