We prove that if Köthe F-spaces X and Y on finite atomless measure spaces (ΩX; ΣX, µX) and (ΩY; ΣY; µY), respectively, with absolute continuous norms are isomorphic and have the property (for µ = µX and µ = µY, respectively) then the measure spaces (ΩX; ΣX; µX) and (ΩY; ΣY; µY) are isomorphic, up to some positive multiples. This theorem extends a result of A. Plichko and M. Popov concerning isomorphic classification of L p(µ)-spaces for 0 < p < 1. We also provide a new class of F-spaces having no nonzero separable quotient space.
@article{bwmeta1.element.doi-10_2478_s11533-011-0079-y, author = {Violetta Kholomenyuk and Volodymyr Mykhaylyuk and Mikhail Popov}, title = {On isomorphisms of some K\"othe function F-spaces}, journal = {Open Mathematics}, volume = {9}, year = {2011}, pages = {1267-1275}, zbl = {1238.46002}, language = {en}, url = {http://dml.mathdoc.fr/item/bwmeta1.element.doi-10_2478_s11533-011-0079-y} }
Violetta Kholomenyuk; Volodymyr Mykhaylyuk; Mikhail Popov. On isomorphisms of some Köthe function F-spaces. Open Mathematics, Tome 9 (2011) pp. 1267-1275. http://gdmltest.u-ga.fr/item/bwmeta1.element.doi-10_2478_s11533-011-0079-y/
[1] Lacey H.E., The Isometric Theory of Classical Banach Spaces, Grundlehren Math. Wiss., 208, Springer, Berlin-Heidelberg-New York, 1974 | Zbl 0285.46024
[2] Lindenstrauss J., Some open problems in Banach space theory, Séminaire Choquet, Initiation à l’Analyse, 1975–76, 15, #18
[3] Maharam D., On homogeneous measure algebras, Proc. Natl. Acad. Sci. USA, 1942, 28, 108–111 http://dx.doi.org/10.1073/pnas.28.3.108 | Zbl 0063.03723
[4] Plichko A.M., Popov M.M., Symmetric Function Spaces on Atomless Probability Spaces, Dissertationes Math. (Rozprawy Mat.), 306, Polish Academy of Sciences, Warsaw, 1990
[5] Popov M.M., On codimension of subspaces of L p(µ) for p < 1, Funktsional. Anal. i Prilozhen., 1984, 18(2), 94–95 (in Russian) http://dx.doi.org/10.1007/BF01077844
[6] Popov M.M., An isomorphic classification of the spaces L p for 0 < p < 1, Teor. Funktsiĭ Funktsional. Anal. i Prilozhen., 1987, 47, 77–85 (in Russian)
[7] Rolewicz S., Metric Linear Spaces, 2nd ed., Math. Appl. (East European Ser.), 20, PWN, Warszawa, 1985
[8] Śliwa W., The separable quotient problem for symmetric function spaces, Bull. Polish Acad. Sci. Math., 2000, 48(1), 13–27 | Zbl 0984.46017
[9] Śliwa W., The separable quotient problem for (LF)tv-spaces, J. Korean Math. Soc., 2009, 46(6), 1233–1242 http://dx.doi.org/10.4134/JKMS.2009.46.6.1233 | Zbl 1190.46004