# Article

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Keywords:
topological semigroup; semigroup compactification; inverse spectrum; pseudocompact space; openly factorizable space; openly generated space; Eberlein compact; Corson compact; Valdivia compact
Summary:
We prove that the semigroup operation of a topological semigroup $S$ extends to a continuous semigroup operation on its Stone-Čech compactification $\beta S$ provided $S$ is a pseudocompact openly factorizable space, which means that each map $f:S\to Y$ to a second countable space $Y$ can be written as the composition $f=g\circ p$ of an open map $p:X\to Z$ onto a second countable space $Z$ and a map $g:Z\to Y$. We present a spectral characterization of openly factorizable spaces and establish some properties of such spaces.
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