R-polar
QUESTION
R-polar
Click to reveal answer ANSWER
For a relation $R \subset X \times Y$ and $A \subset X$, the $R$-polar of $A$ is defined as:
$$R^\circ A := \bigcap_{x \in A} Rx \subset Y$$
Properties:
- $A_0 \subset A_1 \implies R^\circ A_0 \supset R^\circ A_1$
- $A \subset (R^-)^\circ (R^\circ A)$
Click to see question - ソースノート: chapter1.md
- カードID: r-polar
- 状態: active