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Well-Ordering Principle

Logic, Foundations and Set Theory

The well-ordering principle states that every non-empty subset of the nonnegative integers contains a least element, meaning the nonnegative integers are well-ordered under their natural magnitude order. The phrase is sometimes used as a synonym for the well-ordering theorem, which states that every set can be well-ordered, and on other occasions is understood as the proposition that the integers contain the natural numbers as a well-ordered subset in which every nonempty subset has a least element.

Facts
Partially Attested
Origin Year
1889 1
Dates Peano's formal publication of the induction axiom (his fifth axiom), which the atlas's own cited Wikipedia source states the well-ordering principle for the natural numbers is derived from in Peano arithmetic. Not the principle's earliest informal use: Fermat's infinite descent already relied on it in the 17th century, before any formal axiomatization.
Connections

Associated With

Sets, Concepts
Source Well-Ordering Principle (Wikipedia)

In Branch

Sources
1. MacTutor History of Mathematics Archive
University of St Andrews, School of Mathematics and StatisticsBiographies/Peano page, paragraph beginning "In 1889 Peano published his famous axioms"
Quote, Biographies/Peano page, paragraph beginning "In 1889 Peano published his famous axioms"
In 1889 Peano published his famous axioms, called Peano axioms, which defined the natural numbers in terms of sets.
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Well-Ordering Principle (Wikipedia)
Wikimedia Foundation
  • Lead section
    In mathematics, the well-ordering principle states that every non-empty subset of nonnegative integers contains a least element.
  • Associated With: Sets, Lead section, first sentence
    the well-ordering principle states that every non-empty subset of nonnegative integers contains a least element
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