In all these pictures, the empty set is missing (-: . Of course you could argue that they’re also missing in Venn diagrams, but it’s common to just point on the outside.
In all these pictures, the empty set is missing (-: . Of course you could argue that they’re also missing in Venn diagrams, but it’s common to just point on the outside.
One example included the empty set, the other did not. It doesn't always make sense to have it.
The three lightgray circles in the examples are the empty set.