Definition of Zorn's lemma
: a lemma in set theory: if a set S is partially ordered and if each subset for which every pair of elements is related by exactly one of the relationships “less than,” “equal to,” or “greater than” has an upper bound in S, then S contains at least one element for which there is no greater element in S — compare axiom of choice
Origin of zorn's lemma
Max August Zorn †1993 German mathematician
First Known Use: circa 1950
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