(Q3123369)
Statements
Identifiers
Sitelinks
Wikipedia(9 entries)
- cswiki Sigma okruh
- dewiki Σ-Ring
- enwiki Sigma-ring
- frwiki Sigma-anneau
- jawiki Σ集合環
- plwiki Σ-pierścień
- skwiki Sigma-okruh
- ukwiki Сигма-кільце
- zhwiki Σ环
Family closed under countable unions and relative complements