Difference between revisions of "Least upper bound"
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− | Given a [[subset]] <math>S</math> in some larger [[ordered set]] <math>R</math>, a '''least upper bound''' | + | Given a [[subset]] <math>S</math> in some larger [[ordered set]] <math>R</math>, a '''least upper bound''' or '''supremum''', for <math>S</math> is an [[element]] <math>\displaystyle M \in R</math> such that <math>s \leq M</math> for every <math>s \in S</math> and there is no <math>m < M</math> with this same property. |
If the least upper bound <math>M</math> of <math>S</math> is an element of <math>S</math>, it is also the [[maximum]] of <math>S</math>. If <math>M \not\in S</math>, then <math>S</math> has no maximum. | If the least upper bound <math>M</math> of <math>S</math> is an element of <math>S</math>, it is also the [[maximum]] of <math>S</math>. If <math>M \not\in S</math>, then <math>S</math> has no maximum. |
Revision as of 07:06, 4 November 2006
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Given a subset in some larger ordered set , a least upper bound or supremum, for is an element such that for every and there is no with this same property.
If the least upper bound of is an element of , it is also the maximum of . If , then has no maximum.