In mathematics, an empty set refers to a set that does not contain any elements.

A power set is a set consisting of all subsets of a set.

In math class, we learned about the intersection.

In math class, we learned about the concept of union sets.

There is a communal letterbox in our apartment.

He pointed at the location on the map.

He was counting money all day long.

The success of this project is a combination of many components.

In set theory, the symmetric difference indicates the difference between two sets.

She has trypophobia, and feels discomfort when she sees things with many holes like beehives or corals.