Image and Preimage
QUESTION
Image and Preimage
Click to reveal answer ANSWER
For $A \subset X$ and $B \subset Y$:
- **Image** of $A$ under $R$: $R(A) \text{ or } RA := \{y \in Y : \exists x \in A, (x, y) \in R\}$
- **Preimage** of $B$ under $R$: $R^-B := \{x \in X : \exists y \in B, (x, y) \in R\}$
- Notation: $Rx := R(\{x\})$ and $R^-y := R^-(\{y\})$.
Click to see question - ソースノート: chapter1.md
- カードID: image-and-preimage
- 状態: active