Definition:Finer Filter on Set/Strictly Finer

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Let $S$ be a set.

Let $\powerset S$ be the power set of $S$.

Let $\FF, \FF' \subset \powerset S$ be two filters on $S$.

Let $\FF \subset \FF'$, that is, $\FF \subseteq \FF'$ but $\FF \ne \FF'$.

Then $\FF'$ is strictly finer than $\FF$.

Also known as

A strictly finer filter than $\FF$ can also be referred to as a proper superfilter of $\FF$.

However, this is not encouraged, as there exists the danger of confusing this with the concept of a proper filter.

Also see