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An Example of a Compact Space of Uncountable Character for Which the Space $\exp_n(X)\setminus X$ is Normal
A. V. Ivanov Petrozavodsk State University
Abstract:
Under Jensen's axiom, a compact space $X$ of uncountable character such that the space $\exp_n(X)\setminus X$ is normal for each $n$ is constructed. Thereby, it is proved that the Arkhangelskii–Kombarov theorem on the countability of the character of a compact space whose square is normal outside the diagonal cannot be “naïvely” carried over to normal functors of finite degree.
Keywords:
Katětov's theorem, square of a compact space, first-countable compact space, functor $\exp_n$, Jensen's axiom, normal functor.
Received: 27.01.2013 Revised: 09.08.2013
Citation:
A. V. Ivanov, “An Example of a Compact Space of Uncountable Character for Which the Space $\exp_n(X)\setminus X$ is Normal”, Mat. Zametki, 98:2 (2015), 221–229; Math. Notes, 98:2 (2015), 251–257
Linking options:
https://www.mathnet.ru/eng/mzm10237https://doi.org/10.4213/mzm10237 https://www.mathnet.ru/eng/mzm/v98/i2/p221
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