Boyanov–Naidenov problem and the Kolmogorov-type inequalities for functions on the real axis

• Date: 2025
• Main Authors: Kofanov, V., Кофанов, Владимир Александрович, Кофанов, Володимир
• Format: Article
• Language: Ukrainian
• Published: Institute of Mathematics, NAS of Ukraine 2025
• Online Access: https://umj.imath.kiev.ua/index.php/umj/article/view/8538
• Journal Title: Ukrains’kyi Matematychnyi Zhurnal

UDC 517.5 We solve the Boyanov–Naidenov problem $\big\|x^{(k)}\big\|_{q,\, \delta} \to \sup,$ $k= 1,\ldots ,r-1,$ $q \ge 1,$ on the classes of functions $W^r_{p,\varepsilon}(A_0, A_r):=\big\{x\in L^r_{\infty}\colon \|x\|_{p, \varepsilon} \le A_0 ,\ \big\|x^{(r)...