Wieners problem for positive definite functions

We study the sharp constant Wn(D) in Wieners inequality for positive definite functions ∫Tn|f|2dx≤Wn(D)|D|-1∫D|f|2dx,D⊂Tn.Wiener proved that W1([- δ, δ]) < ∞, δ∈ (0 , 1 / 2). Hlawka showed that Wn(D) ≤ 2 n, where D is an origin-symmetric convex body. We sharpen Hlawkas estimates for D being t...

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Detalles Bibliográficos
Autores: Gorbachev, D.V., Tikhonov, S.Y.
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2018
País:España
Institución:Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)
Repositorio:Recercat. Dipósit de la Recerca de Catalunya
OAI Identifier:oai:recercat.cat:2072/445765
Acceso en línea:http://hdl.handle.net/2072/445765
Access Level:acceso abierto
Palabra clave:51
Descripción
Sumario:We study the sharp constant Wn(D) in Wieners inequality for positive definite functions ∫Tn|f|2dx≤Wn(D)|D|-1∫D|f|2dx,D⊂Tn.Wiener proved that W1([- δ, δ]) < ∞, δ∈ (0 , 1 / 2). Hlawka showed that Wn(D) ≤ 2 n, where D is an origin-symmetric convex body. We sharpen Hlawkas estimates for D being the ball δBn and the cube δIn. In particular, we prove that Wn(δBn) ≤ 2 ( 0.401 ⋯ + o ( 1 ) ) n. We also obtain a lower bound of Wn(D). Moreover, for a cube D=1qIn with q= 3 , 4 , … , we obtain that Wn(D) = 2 n. Our proofs are based on the interrelation between Wieners problem and the problems of Turán and Delsarte. © 2017, Springer-Verlag GmbH Deutschland.