英语词汇“sigma ring”的英英意思、用法、释义、翻译、读音、例句、短语、词组-英语词典

单词	sigma ring
释义	sigma ring sigma ring [′sig·mə ‚riŋ] (mathematics) A ring of sets where any countable union of its members is also a member.
随便看	widow's benefits widows benefits widow's chamber widow's cruse widow's election widow's exemption widows exemption widow's exemptions widows exemptions widow's mite widow's mites widow's peak widow's-peak widows peak widow's peaks widow spider widow's son of nain widow's walk widows walk widow's walks widow's weeds widows weeds widows' weeds widow's weeds (album) widow-wail

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