Abstract:
We prove that the Zygmund space L(lnL)1/2L(lnL)1/2 is the greatest one in the set of symmetric spaces XX for which any uniformly bounded orthonormal system of functions contains a sequence such that the corresponding space of Fourier coefficients F(X)F(X) coincides with ℓ2ℓ2. Similar results also hold for symmetric spaces located between the spaces L(lnL)1/2L(lnL)1/2 and L1L1.
Keywords:
orthonormal system, Fourier coefficients, symmetric space, real interpolation method.
The work of the first author was supported
by the Ministry of Education and Science of the Russian Federation.
The work of the second author was supported
by the Russian Foundation for Basic Research
under grant 14-01-00141a.
Citation:
S. V. Astashkin, E. M. Semenov, “On Fourier Coefficients of Lacunary Systems”, Mat. Zametki, 100:4 (2016), 483–491; Math. Notes, 100:4 (2016), 507–514
This publication is cited in the following 2 articles:
M. Junge, F. Sukochev, D. Zanin, “Embeddings of operator ideals intoLp-spaces on finite von Neumann algebras”, Advances in Mathematics, 312 (2017), 473
Sergey V. Astashkin, “Rademacher series and isomorphisms of rearrangement invariant spaces on the finite interval and on the semi-axis”, Journal of Functional Analysis, 260:1 (2011), 195