Filter (フィルター)
QUESTION
Filter (フィルター)
Click to reveal answer ANSWER
Let $X$ be a non-empty set. A family $\mathcal{F}$ of subsets of $X$ is called a **filter** on $X$ if it is:
1. **Isotone**: $F \in \mathcal{F}$ and $F \subset G \implies G \in \mathcal{F}$
2. **Finitely Complete**: $F_0, F_1 \in \mathcal{F} \implies F_0 \cap F_1 \in \mathcal{F}$
Click to see question - ソースノート: chapter2.md
- カードID: filter
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