Playing with Clubs

Now that we know about Secret Clubs, let’s see how we can mix and match them! We call these Set Operations, but they’re really just rules for who’s invited.

The “Everyone’s Invited” Party (Union)

Select the sections where EVERYONE from Club A and Club B is invited!

This is everyone in A, everyone in B, and everyone who belongs to both!

The “Double Member” Club (Intersection)

Select the section for people who belong to BOTH Club A and Club B.

Only the people who are double-members are allowed here!

The “Only-A” Fan Club (Difference)

Select the section for people who are in Club A, but NOT in Club B.

We want the members of A who haven’t joined B yet.

The “Outsiders” Club (Complement)

Select the sections for people who are NOT in Club A.

This includes people in Club B who aren’t in Club A, and everyone else who didn’t join any club!