In math class, the teacher explained the concept of relative complement.

The concept of the absolute complement plays an important role in set theory.

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

In math class, I learned about the concept of intersection.

He wants to learn deeply about set theory.

He pointed at the location on the map.

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

He was counting money all day long.

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

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