# non-well-founded set theory

> variants of axiomatic set theory that allow sets to be elements of themselves

**Wikidata**: [Q7049089](https://www.wikidata.org/wiki/Q7049089)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Non-well-founded_set_theory)  
**Source**: https://4ort.xyz/entity/non-well-founded-set-theory