The Empty operator is a Boolean operator that is used to check if a collection or string is empty or not. It returns true if the collection or string has no elements, and false otherwise. It can be used with any collection type, including sets, sequences, and bags, as well as with strings.

Here are a few examples of how the Empty operator can be used:

1. Checking if a sequence is empty:

sequence1.empty()

This will return true if "sequence1" is empty, and false otherwise.

2. Checking if a set is empty:

set1.empty()

This will return true if "set1" is empty, and false otherwise.

3. Checking if a string is empty:

string1.empty()

This will return true if "string1" is empty, and false otherwise.