On the Lebesgue constants

• Date: 2019
• Main Authors: Kushpel, A. K., Кушпель, А. К.
• Format: Article
• Language: Russian
• Published: Institute of Mathematics, NAS of Ukraine 2019
• Online Access: https://umj.imath.kiev.ua/index.php/umj/article/view/1499
• Journal Title: Ukrains’kyi Matematychnyi Zhurnal

UDC 517.5 We give the solution of a classical problem of approximation theory on sharp asymptotic of the Lebesgue constants or norms of the Fourier – Laplace projections on the real spheres $\mathbb{S}^{d},$ complex $\mathrm{P}^{d}(\mathbb{C})$ and quaternionic $\mathrm{P}^{d}(\mathbb{H})$ proje...