# INTERSECTION

### Description

The `INTERSECTION` function takes two lists and returns a new list containing only the elements that appear in **both** lists. Elements present in only one of the two lists are excluded from the result.

### Syntax

```
INTERSECTION(list_a, list_b)
```

**Returns:** A list of elements that exist in both `list_a` and `list_b`.

### Example

```
p is Person
INTERSECTION(p.countries_lived_in, p.nationalities)
```

This returns the countries the person has both lived in and holds a nationality for. For example, if a person has lived in Germany, Switzerland, and Italy, but only holds German nationality, the result would be `[Germany]`.