Topological semigroup
In mathematics, a topological semigroup is a semigroup which is simultaneously a topological space, and whose semigroup operation is continuous.
A topological group is a topological semigroup.
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Wikipedia
In mathematics, a topological semigroup is a semigroup which is simultaneously a topological space, and whose semigroup operation is continuous.
A topological group is a topological semigroup.