# Conceptset

### Description

A Conceptset or Multi Select is a collection of concepts. Duplicates can never occur in the same collection and are filtered out.

### Formatting

Concepts in single quotes, separated by a comma and enclosed with curly brackets `{}`.&#x20;

```
{ 'Color'.'Orange', 'Color'.'Blue', 'Color'.'Red' }
/* a set of concepts with the colors Orange, Blue and Red */

{ } 
/* one empty set = not an unknown set, rather a known set with 0 concepts */

{ 'Color'.'Orange', 'Color'.'Blue' } + { 'Color'.'Orange', 'Color'.'Red' }
= { 'Color'.'Orange', 'Color'.'Blue', 'Color'.'Red' }
/* no duplicates when combining 2 sets with overlapping concepts */
```

### Unknown

An unknown value can be written as `UnknownConceptset`

### Remarks

A field that has a concept set value is called a "multi select" field.&#x20;