Set-builder notation

Set-builder notation is a way to describe a group of objects (called a set) by defining a rule that all members follow. Instead of listing every item, you specify the criteria they meet. For example, {x | x > 0} describes all numbers greater than zero. The vertical bar reads as "such that," meaning the set contains all elements x that satisfy the condition after it. It’s a concise way to define potentially large or infinite sets by their common properties.