Abstract
We give the solution of the Turán extremal problem for compact supported functions on the half-line with nonnegative Jacobi transform and the dual Fejér extremal problem for even nonnegative entire functions of exponential type that are Jacobi transforms. We prove the uniqueness of the extremal functions. The Markov quadrature formula on the half-line at zeros of the modified Jacobi function is used for the proof of these results.
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This work was supported by the Russian Foundation for Basic Research under grant 16-01-00308.
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Gorbachev, D.V., Ivanov, V.I. Turán’s and Fejér’s Extremal Problems for Jacobi Transform. Anal Math 44, 419–432 (2018). https://doi.org/10.1007/s10476-018-0304-z
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DOI: https://doi.org/10.1007/s10476-018-0304-z
Key words and phrases
- hyperbolic weight
- Jacobi function
- Jacobi transform
- Turán extremal problem
- Fejér extremal problem
- entire function of exponential type
- Markov quadrature formula