We prove that a separable Hausdor_ topological space X containing a cocountable subset homeomorphic to [0, ω1] admits no separately continuous mean operation and no diagonally continuous n-mean for n ≥ 2.
@article{bwmeta1.element.doi-10_2478_taa-2014-0002, author = {T. Banakh and R. Bonnet and W. Kubis}, title = {Means on scattered compacta}, journal = {Topological Algebra and its Applications}, volume = {2}, year = {2014}, zbl = {1310.54023}, language = {en}, url = {http://dml.mathdoc.fr/item/bwmeta1.element.doi-10_2478_taa-2014-0002} }
T. Banakh; R. Bonnet; W. Kubis. Means on scattered compacta. Topological Algebra and its Applications, Tome 2 (2014) . http://gdmltest.u-ga.fr/item/bwmeta1.element.doi-10_2478_taa-2014-0002/
[1] G. Aumann, Aufau von Mittelwerten mehrerer Argumente. II. (Analytische Mittelwerte), Math. Ann. 111:1 (1935), 713-730. | Zbl 0012.25205
[2] G. Aumann, Über Räume mit Mittelbildungen, Math. Ann. 119 (1944), 210-215. | Zbl 0060.40005
[3] G. Aumann, C. Carathéodory, Ein Satz über die konforme Abbildung mehrfach zusammenhängender ebener Gebiete, Math.Ann. 109 (1934), 756-763. | Zbl 60.0285.04
[4] T. Banakh, O. Gutik, M. Rajagopalan, On algebraic structures on scattered compacta, Topology Appl. 153:5-6 (2005), 710-723. | Zbl 1087.22003
[5] R. Bonnet, W. Kubis, Semilattices, unpublished note.
[6] B. Eckmann, Räume mit Mittelbildung, Comm. Math. Helv. 28 (1954), 329-340. | Zbl 0056.16403
[7] P. Hilton, A new look at means on topological spaces, Internat. J. Math. Math. Sci. 20:4 (1997), 617-620. [Crossref] | Zbl 0907.55010
[8] K. Hofmann, M. Mislove, A. Stralka, The Pontryagin duality of compact O-dimensional semilattices and its applications, Lecture Notes in Math., Vol. 396. Springer-Verlag, Berlin-New York, 1974. | Zbl 0281.06004
[9] I. Parovichenko, On a universal bicompactum of weight @, Dokl. Akad. Nauk SSSR, 150 (1963), 36-39.
[10] A. Teleiko, M. Zarichnyi, Categorical Topology of Compact Hausdor_ spaces, VNTL Publ., Lviv, 1999. | Zbl 1032.54004
[11] F. Trigos-Arrieta, M. Turzanski, On Aumann’s theorem that the circle does not admit a mean, Acta Univ. Carolin. Math. Phys. 46:2 (2005), 77-82.