Abstract:
It is shown that the supercardinality of a completely regular space $X$ equivalent to a dyadic space is equal to $\exp(\pi wX)$ provided $(\pi wX)^{\omega_0}=\pi wX$, where $\pi wX$ is the $\pi$-weight of $X$. In particular, it follows that the supercardinality of any countable dense subspace of a dyadic compactum of weight $\exp\omega_0$ is equal to $\exp\exp\omega_0$. This solves a problem raised by A. V. Arkhangel'skii on whether there exists a countable completely regular space whose every compactification has a cardinality larger than the continuum.
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