# Sets, rules and natural classes: [ ] vs. { }

> Research article (Loquens, 2019) · cited 83× · AI/ML

**Wikidata**: [openalex:W3109392859](https://www.wikidata.org/wiki/openalex:W3109392859)  
**Source**: https://4ort.xyz/entity/sets-rules-and-natural-classes-vs