Definition:Horizontal Section of Set

Definition

Let $X$ and $Y$ be sets.

Let $E \subseteq X \times Y$.

Let $y \in Y$.

We define the $y$-horizontal section $E^y$ of $E$ by:

$E^y = \set {x \in X : \tuple {x, y} \in E}$

Sources

• 2013: Donald L. Cohn: Measure Theory (2nd ed.) ... (previous) ... (next): $5.1$: Constructions